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<p><a id="X780A68B584B7F3DF" name="X780A68B584B7F3DF"></a></p>
<div class="ChapSects"><a href="chap1.html#X780A68B584B7F3DF">1 <span class="Heading">Introduction to the <strong class="pkg">AtlasRep</strong> Package</span></a>
<div class="ContSect"><span class="tocline"><span class="nocss"> </span><a href="chap1.html#X7A76DF957E7AF8AE">1.1 <span class="Heading">The <strong class="pkg">ATLAS</strong> of Group Representations</span></a>
</span>
</div>
<div class="ContSect"><span class="tocline"><span class="nocss"> </span><a href="chap1.html#X8033B61682EE6A23">1.2 <span class="Heading">The GAP Interface to the <strong class="pkg">ATLAS</strong> of Group Representations</span></a>
</span>
</div>
<div class="ContSect"><span class="tocline"><span class="nocss"> </span><a href="chap1.html#X7B864EDC7CB211FD">1.3 <span class="Heading">What's New in <strong class="pkg">AtlasRep</strong>, Compared to Older Versions?</span></a>
</span>
<div class="ContSSBlock">
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7E024E377C2E8C27">1.3-1 <span class="Heading">What's New in Version 2.1.9?
(August 2024)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X85FE8BE580751F58">1.3-2 <span class="Heading">What's New in Version 2.1.8? (January 2024)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7B5DB23579AD1066">1.3-3 <span class="Heading">What's New in Version 2.1.7? (August 2023)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7D4644167F6C9D4C">1.3-4 <span class="Heading">What's New in Version 2.1.6? (October 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X823B2D767C11246A">1.3-5 <span class="Heading">What's New in Version 2.1.5? (August 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7BEBD3618260FE03">1.3-6 <span class="Heading">What's New in Version 2.1.4? (August 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7DB709CD7FECC9B1">1.3-7 <span class="Heading">What's New in Version 2.1.3? (August 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7A2A60D7841AF2CE">1.3-8 <span class="Heading">What's New in Version 2.1.2? (March 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7B0E14E57E9FC37E">1.3-9 <span class="Heading">What's New in Version 2.1.1? (February 2022)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7DA8E7647A422775">1.3-10 <span class="Heading">What's New in Version 2.1.0? (May 2019)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7EACAC887E257302">1.3-11 <span class="Heading">What's New in Version 1.5.1? (March 2016)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X86002B747AE0741B">1.3-12 <span class="Heading">What's New in Version 1.5? (July 2011)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X878EBA108716DDF0">1.3-13 <span class="Heading">What's New in Version 1.4? (June 2008)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X87A53CE182C9E086">1.3-14 <span class="Heading">What's New in Version 1.3.1? (October 2007)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X79CCC5517897924C">1.3-15 <span class="Heading">What's New in Version 1.3? (June 2007)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X7BDCA94D83DCFFB8">1.3-16 <span class="Heading">What's New in Version 1.2? (November 2003)</span></a>
</span>
<span class="ContSS"><br /><span class="nocss"> </span><a href="chap1.html#X831628B47F669B29">1.3-17 <span class="Heading">What's New in Version 1.1? (October 2002)</span></a>
</span>
</div></div>
<div class="ContSect"><span class="tocline"><span class="nocss"> </span><a href="chap1.html#X82A988D47DFAFCFA">1.4 <span class="Heading">Acknowledgements</span></a>
</span>
</div>
</div>
<h3>1 <span class="Heading">Introduction to the <strong class="pkg">AtlasRep</strong> Package</span></h3>
<p>The aim of the <strong class="pkg">GAP</strong> 4 package <strong class="pkg">AtlasRep</strong> is to provide a link between <strong class="pkg">GAP</strong> and databases such as the <strong class="pkg">ATLAS</strong> of Group Representations <a href="chapBib.html#biBAGRv3">[WWT+]</a>, which comprises generating permutations and matrices for many almost simple groups, and information about their maximal subgroups. This database is available independent of <strong class="pkg">GAP</strong> at</p>
<p><span class="URL"><a href="http://atlas.math.rwth-aachen.de/Atlas/v3">http://atlas.math.rwth-aachen.de/Atlas/v3</a></span>.</p>
<p>The <strong class="pkg">AtlasRep</strong> package consists of this database (see Section <a href="chap1.html#X7A76DF957E7AF8AE"><span class="RefLink">1.1</span></a>) and a <strong class="pkg">GAP</strong> interface (see Section <a href="chap1.html#X8033B61682EE6A23"><span class="RefLink">1.2</span></a>); the latter is extended by further information available via the internet (see Section <a href="chap4.html#X7C50F18587ADC3B5"><span class="RefLink">4.3</span></a>).</p>
<p>This package manual has the following parts.</p>
<dl>
<dt><strong class="Mark">A tutorial</strong></dt>
<dd><p>gives an overview how the functions of the package can be used, see Chapter <a href="chap2.html#X8171B3798425E183"><span class="RefLink">2</span></a>.</p>
</dd>
<dt><strong class="Mark">User interface functions</strong></dt>
<dd><p>are described in Chapter <a href="chap3.html#X87EAF8E578D95793"><span class="RefLink">3</span></a>.</p>
</dd>
<dt><strong class="Mark">Customizations of the package</strong></dt>
<dd><p>are described in Chapter <a href="chap4.html#X797694467B534D0E"><span class="RefLink">4</span></a>.</p>
</dd>
<dt><strong class="Mark">Information how to extend the database</strong></dt>
<dd><p>can be found in Chapter <a href="chap5.html#X7B0718A178BB10CA"><span class="RefLink">5</span></a>.</p>
</dd>
<dt><strong class="Mark">More technical information</strong></dt>
<dd><p>can be found in the chapters <a href="chap6.html#X83827EDB7D36C407"><span class="RefLink">6</span></a> (concerning <strong class="pkg">GAP</strong> objects that are introduced by the package) and <a href="chap7.html#X7F77634D817156B3"><span class="RefLink">7</span></a> (concerning global variables and sanity checks).</p>
</dd>
</dl>
<p><a id="X7A76DF957E7AF8AE" name="X7A76DF957E7AF8AE"></a></p>
<h4>1.1 <span class="Heading">The <strong class="pkg">ATLAS</strong> of Group Representations</span></h4>
<p>The <strong class="pkg">ATLAS</strong> of Group Representations <a href="chapBib.html#biBAGRv3">[WWT+]</a> consists of matrices over various rings, permutations, and shell scripts encoding so-called black box programs (see <a href="chapBib.html#biBNic06">[Nic06]</a> and Section <a href="chap6.html#X7BE856BC785A9E8F"><span class="RefLink">6.2</span></a>). Many of these scripts are straight line programs (see <a href="chapBib.html#biBBSW01">[BSWW01]</a>, <a href="chapBib.html#biBSWW00">[SWW00]</a>, and <a href="../../../doc/ref/chap37.html#X7DC99E4284093FBB"><span class="RefLink">Reference: Straight Line Programs</span></a>) and straight line decisions (see Section <a href="chap6.html#X8121E9567A7137C9"><span class="RefLink">6.1</span></a>). These programs can be used to compute certain elements in a group <span class="SimpleMath">G</span> from its standard generators (see <a href="chapBib.html#biBWil96">[Wil96]</a> and Section <a href="chap3.html#X795DB7E486E0817D"><span class="RefLink">3.3</span></a>) for example generators of maximal subgroups of <span class="SimpleMath">G</span> or representatives of conjugacy classes of <span class="SimpleMath">G</span>.</p>
<p>The <strong class="pkg">ATLAS</strong> of Group Representations has been prepared by Robert Wilson, Peter Walsh, Jonathan Tripp, Ibrahim Suleiman, Richard Parker, Simon Norton, Simon Nickerson, Steve Linton, John Bray, and Rachel Abbott (in reverse alphabetical order).</p>
<p>The information was computed and composed using computer algebra systems such as <strong class="pkg">MeatAxe</strong> (see <a href="chapBib.html#biBCMeatAxe">[Rin]</a>), Magma (see <a href="chapBib.html#biBCP96">[CP96]</a>), and <strong class="pkg">GAP</strong> (in reverse alphabetical order). Part of the constructions have been documented in the literature on almost simple groups, or the results have been used in such publications, see for example the bibliographies in <a href="chapBib.html#biBCCN85">[CCN+85]</a> and <a href="chapBib.html#biBBN95">[BN95]</a> which are available online at <span class="URL"><a href="http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep/bibl">http://www.math.rwth-aachen.de/~Thomas.Breuer/atlasrep/bibl</a></span>.</p>
<p>If you use the <strong class="pkg">ATLAS</strong> of Group Representations to solve a problem then please send a short email to <span class="URL"><a href="mailto:R.A.Wilson@qmul.ac.uk">R.A.Wilson@qmul.ac.uk</a></span> about it. The <strong class="pkg">ATLAS</strong> of Group Representations database should be referenced with the entry <a href="chapBib.html#biBAGRv3">[WWT+]</a> in the bibliography of this manual.</p>
<p>If your work made use of functions of the <strong class="pkg">GAP</strong> interface (see Section <a href="chap1.html#X8033B61682EE6A23"><span class="RefLink">1.2</span></a>) then you should also reference this interface, using the information printed by the <strong class="pkg">GAP</strong> function <code class="func">Cite</code> (<a href="../../../doc/ref/chap76.html#X79637D9A7B1AD7F7"><span class="RefLink">Reference: Cite</span></a>).</p>
<p>For referencing the <strong class="pkg">GAP</strong> system in general, use the entry <a href="chapBib.html#biBGAP">[GAP19]</a> in the bibliography of this manual, see also <span class="URL"><a href="http://www.gap-system.org">http://www.gap-system.org</a></span>.</p>
<p><a id="X8033B61682EE6A23" name="X8033B61682EE6A23"></a></p>
<h4>1.2 <span class="Heading">The GAP Interface to the <strong class="pkg">ATLAS</strong> of Group Representations</span></h4>
<p>The <strong class="pkg">GAP</strong> interface to the <strong class="pkg">ATLAS</strong> of Group Representations consists of essentially two parts.</p>
<ul>
<li><p>First, there is the <em>user interface</em> which allows the user to get an overview of the contents of the database, and to access the data in <strong class="pkg">GAP</strong> format; this is described in Chapter <a href="chap3.html#X87EAF8E578D95793"><span class="RefLink">3</span></a>. Advanced users may add their own data to the database, this is described in Chapter <a href="chap5.html#X7B0718A178BB10CA"><span class="RefLink">5</span></a>.</p>
</li>
<li><p>Second, there is <em>administrational information</em>, which covers also the declaration of <strong class="pkg">GAP</strong> objects such as straight line decisions and black box programs. This is important mainly for users interested in the actual implementation (e. g., for modifying the package) or in using it together with the <code class="code">C</code>-<strong class="pkg">MeatAxe</strong> standalone (see <a href="chapBib.html#biBCMeatAxe">[Rin]</a>); this is described in Chapter <a href="chap7.html#X7F77634D817156B3"><span class="RefLink">7</span></a>.</p>
</li>
</ul>
<p>Information concerning the <code class="code">C</code>-<strong class="pkg">MeatAxe</strong>, including the manual <a href="chapBib.html#biBCMeatAxe">[Rin]</a>, can be found at</p>
<p><span class="URL"><a href="http://www.math.rwth-aachen.de/~MTX">http://www.math.rwth-aachen.de/~MTX</a></span></p>
<p>The interface and this manual have been provided by Thomas Breuer, except for the interpreter for black box programs (see Section <a href="chap6.html#X7BE856BC785A9E8F"><span class="RefLink">6.2</span></a>), which is due to Simon Nickerson. Comments, bug reports, and hints for improving the interface can be sent to <span class="URL"><a href="mailto:sam@math.rwth-aachen.de">sam@math.rwth-aachen.de</a></span>.</p>
<p><a id="X7B864EDC7CB211FD" name="X7B864EDC7CB211FD"></a></p>
<h4>1.3 <span class="Heading">What's New in <strong class="pkg">AtlasRep</strong>, Compared to Older Versions?</span></h4>
<p><a id="sect:news"/></p>
<p><a id="X7E024E377C2E8C27" name="X7E024E377C2E8C27"></a></p>
<h5>1.3-1 <span class="Heading">What's New in Version 2.1.9?
(August 2024)</span></h5>
<ul>
<li><p>Now prescribing a ring in <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>) and related functions automatically prescribes its characteristic. Up to now, one had to specify also the characteristic, otherwise characteristic zero was erroneously assumed.</p>
</li>
<li><p>Up to now, <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>) and related functions, when called only with a prescribed ring in positive characteristic, could erroneously return also entries about representations in characteristic zero.</p>
</li>
<li><p>The default for the user preference <code class="code">"AtlasRepDataDirectory"</code> (see Section <a href="chap4.html#X7C36E9A78021A71A"><span class="RefLink">4.2-2</span></a>) has been improved in the situation where the package directory is not writable <em>and</em> the <strong class="pkg">GAP</strong> session runs inside a <strong class="pkg">Julia</strong> session; if this is the case then a <strong class="pkg">Julia</strong> scratchspace is used as the default.</p>
</li>
<li><p>The star <code class="code">*</code> that may appear in some lines of the output of <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) is now documented. Thanks to Will Chen for reporting that an explanation for it was missing.</p>
</li>
</ul>
<p><a id="X85FE8BE580751F58" name="X85FE8BE580751F58"></a></p>
<h5>1.3-2 <span class="Heading">What's New in Version 2.1.8? (January 2024)</span></h5>
<p>An example in Section <a href="chap2.html#X826C681B7EB3B67A"><span class="RefLink">2.1-2</span></a> of the Tutorial had to be adjusted because the results of the function <code class="func">SmallerDegreePermutationRepresentation</code> (<a href="../../../doc/ref/chap43.html#X8086628878AFD3EA"><span class="RefLink">Reference: SmallerDegreePermutationRepresentation</span></a>) depend on random computations, in particular the implementation in <strong class="pkg">GAP</strong> 4.13 may yield a nicer representation than had been shown before.</p>
<p><a id="X7B5DB23579AD1066" name="X7B5DB23579AD1066"></a></p>
<h5>1.3-3 <span class="Heading">What's New in Version 2.1.7? (August 2023)</span></h5>
<ul>
<li><p>Requesting certain matrix groups in characteristic zero had caused an error in version 2.1.6, provided that the feature to store downloaded files was disabled, that is, the value of the user preference <code class="code">"AtlasRepDataDirectory"</code> (see Section <a href="chap4.html#X7C36E9A78021A71A"><span class="RefLink">4.2-2</span></a>) was an empty string. This bug is now fixed. Thanks to Lixin Zheng for reporting this problem.</p>
</li>
<li><p>The name of a maximal subgroup of the group <span class="SimpleMath">M_12.2</span> had to be changed from <code class="code">"D8.(S4x2)"</code> to <code class="code">"2^3.(S4×2)"</code> because the old name suggested a wrong group structure. This bug had been announced in <span class="URL"><a href="https://math.stackexchange.com/questions/4577016/group-names-in-gap-character-table-library">a StackExchange discussion</a></span>.</p>
</li>
<li><p>A typo in the documentation of <code class="code">AGR.MXS</code> (see Section <a href="chap7.html#X7B1DECF080AEB806"><span class="RefLink">7.8</span></a>) was fixed. Thanks to Max Horn for spotting this.</p>
</li>
<li><p><strong class="pkg">GAP</strong> 4.13 will provide the new <q>package extension</q> feature, which allows a package to execute <strong class="pkg">GAP</strong> code <em>after</em> the package and some other required packages have been loaded. In <strong class="pkg">AtlasRep</strong>, this feature is now used for example in order to achieve that those functions which depend on the <strong class="pkg">Browse</strong> package can be used also if this package gets (installed and) loaded after <strong class="pkg">AtlasRep</strong> has been loaded.</p>
</li>
<li><p>The code for building the documentation of the package has been adjusted to <span class="URL"><a href="https://github.com/gap-system/gap/pull/5178">a change in <strong class="pkg">GAP</strong> 4.13</a></span>. This does not affect most users of the package because the package archive contains a ready documentation.</p>
</li>
</ul>
<p><a id="X7D4644167F6C9D4C" name="X7D4644167F6C9D4C"></a></p>
<h5>1.3-4 <span class="Heading">What's New in Version 2.1.6? (October 2022)</span></h5>
<p>The package now requires the <strong class="pkg">utils</strong> package <a href="chapBib.html#biButils">[BGH+22]</a>, and uses its <code class="func">Download</code> (<a href="../../../pkg/utils/doc/chap9.html#X7A7438AE8448635E"><span class="RefLink">Utils: Download</span></a>) function for downloading remote files. The former user preference <code class="code">FileTransferTool</code> of the <strong class="pkg">AtlasRep</strong> package is no longer supported; it had been used in older versions to distinguish between different download tools.</p>
<p>A method for <code class="func">ConjugacyClasses</code> (<a href="../../../doc/ref/chap39.html#X871B570284BBA685"><span class="RefLink">Reference: ConjugacyClasses attribute</span></a>) has been added that uses a straight line program for computing class representatives of a group that has been created with <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>), provided such a program is available. Thanks to Frank Lübeck for suggesting this.</p>
<p><a id="X823B2D767C11246A" name="X823B2D767C11246A"></a></p>
<h5>1.3-5 <span class="Heading">What's New in Version 2.1.5? (August 2022)</span></h5>
<p>Two bugs concerning local file permissions and the handling of download failures were fixed. Thanks to Frank Lübeck and Fabian Zickgraf for reporting these problems.</p>
<p><a id="X7BEBD3618260FE03" name="X7BEBD3618260FE03"></a></p>
<h5>1.3-6 <span class="Heading">What's New in Version 2.1.4? (August 2022)</span></h5>
<p>A few changes in the code for downloading files were needed in order to make some CI tests happy.</p>
<p><a id="X7DB709CD7FECC9B1" name="X7DB709CD7FECC9B1"></a></p>
<h5>1.3-7 <span class="Heading">What's New in Version 2.1.3? (August 2022)</span></h5>
<p>The server address for the core part of the database has changed.</p>
<p>Additional table of contents files are now available, which contain checksums in SHA256 format instead of the checksums computed by <code class="func">CrcFile</code> (<a href="../../../doc/ref/chap9.html#X8241CEAD80415BB9"><span class="RefLink">Reference: CrcFile</span></a>) and <code class="func">CrcString</code> (<a href="../../../doc/ref/chap27.html#X7D4B9D7A7995C55D"><span class="RefLink">Reference: CrcString</span></a>). Note that the latter values can be interpreted only by <strong class="pkg">GAP</strong>.</p>
<p>For <span class="SimpleMath">364</span> representations, the corresponding characters have been identified and can thus be used for accessing these representations with <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), see <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>).</p>
<p><a id="X7A2A60D7841AF2CE" name="X7A2A60D7841AF2CE"></a></p>
<h5>1.3-8 <span class="Heading">What's New in Version 2.1.2? (March 2022)</span></h5>
<p>Not much.</p>
<p>The release of Version 2.1.2 was necessary for technical reasons: Now the testfile mentioned in <code class="file">PackageInfo.g</code> exits <strong class="pkg">GAP</strong> in the end, and the external links in the package documentation were corrected (the links in version 2.1.1 pointed to a wrong directory).</p>
<p><a id="X7B0E14E57E9FC37E" name="X7B0E14E57E9FC37E"></a></p>
<h5>1.3-9 <span class="Heading">What's New in Version 2.1.1? (February 2022)</span></h5>
<ul>
<li><p>The new function <code class="func">EvaluatePresentation</code> (<a href="chap3.html#X87B012B080D01413"><span class="RefLink">3.5-11</span></a>) computes the images of the relators of a presentation (see Section <a href="chap6.html#X7C94ECAC8583CEAE"><span class="RefLink">6.1-7</span></a>).</p>
</li>
<li><p>The new function <code class="func">StandardGeneratorsData</code> (<a href="chap3.html#X79F63403821C1E24"><span class="RefLink">3.5-12</span></a>) allows one to compute standard generators from given generators, provided a recipe for that task (a <q>find</q> straight line program) for the group in question is available.</p>
</li>
<li><p>The function <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>) sets known information about the group and the representation, such as <code class="func">IsPrimitive</code> (<a href="../../../doc/ref/chap41.html#X84C19AD68247B760"><span class="RefLink">Reference: IsPrimitive</span></a>).</p>
<p>(Thanks to Steve Linton for suggesting this feature.)</p>
</li>
<li><p>The function <code class="func">ResultOfBBoxProgram</code> (<a href="chap6.html#X869BACFB80A3CC87"><span class="RefLink">6.2-4</span></a>) now admits an optional argument, which is used as options record in calls to <code class="func">RunBBoxProgram</code> (<a href="chap6.html#X7D211A5D8602B330"><span class="RefLink">6.2-3</span></a>).</p>
</li>
<li><p>The new user preference <code class="code">"AtlasRepJsonFilesAddresses"</code> (see Section <a href="chap4.html#X850D135E79EFF3F7"><span class="RefLink">4.2-14</span></a>) allows one to use Json format data files for matrix representations in characteristic zero, which in turn makes it possible to create the matrices over prescribed fields, for example fields returned by <code class="func">AlgebraicExtension</code> (<a href="../../../doc/ref/chap67.html#X7CDA90537D2BAC8A"><span class="RefLink">Reference: AlgebraicExtension</span></a>). The information stored in the table of contents file about the field of entries of the matrix representations has been extended by a <strong class="pkg">GAP</strong> independent description of this field and the defining polynomial used in the Json format data files.</p>
</li>
<li><p>When the value of the user preference <code class="code">"AtlasRepDataDirectory"</code> is an empty string then data files that are fetched from remote servers are read into the <strong class="pkg">GAP</strong> session without storing the files. (An advantage is that one need not care about where one has permissions for storing files. A disadvantage is of course that one has to fetch a file again whenever it is needed.)</p>
</li>
</ul>
<p><a id="X7DA8E7647A422775" name="X7DA8E7647A422775"></a></p>
<h5>1.3-10 <span class="Heading">What's New in Version 2.1.0? (May 2019)</span></h5>
<p>The main differences to earlier versions concern extensions of the available data. Up to now, such extensions were possible only in the sense that one could notify certain <em>locally available files</em> to the package's functions. With this version, it becomes possible to notify also <em>remote data files</em>, i. e., data files which have to be downloaded before they can be read into <strong class="pkg">GAP</strong>, in the same way as the data from the <strong class="pkg">ATLAS</strong> of Group Representations. Two extensions of this kind become automatically available with this package version, see Section <a href="chap5.html#X78E7F7347DE8A125"><span class="RefLink">5.1</span></a> for details.</p>
<p>Thus the focus of the package has changed. In earlier versions, it provided a <strong class="pkg">GAP</strong> interface to the data in the <strong class="pkg">ATLAS</strong> of Group Representations, whereas now this database is regarded as one collection (the <q>core part</q>) among others. Where applicable, the package manual tries to distinguish between general data available to the <strong class="pkg">AtlasRep</strong> functions and the data from the <strong class="pkg">ATLAS</strong> of Group Representations.</p>
<p>In order to provide this new functionality, the following changes have been implemented. Note that some are <em>incompatible changes</em>, compared with earlier versions of the package.</p>
<ul>
<li><p>The format of the <code class="code">identifier</code> components of the records returned by <code class="func">AtlasGenerators</code> (<a href="chap3.html#X7D1CCCF8852DFF39"><span class="RefLink">3.5-3</span></a>), <code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>), etc., has been changed for those data that belong to extensions, see <a href="chap7.html#X7CCA3DE97E756F01"><span class="RefLink">7.7</span></a>. In the new format, the name of the extension is not added to the group name but to the individual filenames; this allows for example the combination of files from the core database and from extensions in one identifier. Functions for converting between the old and the new format are available, see <code class="func">AtlasRepIdentifier</code> (<a href="chap7.html#X81685FC979BC3FB8"><span class="RefLink">7.7-1</span></a>).</p>
</li>
<li><p>The records returned by <code class="func">AtlasGenerators</code> (<a href="chap3.html#X7D1CCCF8852DFF39"><span class="RefLink">3.5-3</span></a>) etc. contain also a component <code class="code">contents</code>, with value the identifier of the part of the database to shich the generators belong.</p>
</li>
<li><p>The tables of contents of the <strong class="pkg">ATLAS</strong> of Group Representations and of extensions are no longer stored in the form of sequences of calls to <strong class="pkg">GAP</strong> functions. Instead, each table of contents is defined via a JSON format file, see <a href="chap6.html#X7E5CB1637F127B2E"><span class="RefLink">6.4</span></a>. In particular, the file <code class="file">atlasprm.json</code> replaces the former <code class="file">gap/atlasprm.g</code>.</p>
<p>Two advantages of this change are that there is no danger to call unwanted <strong class="pkg">GAP</strong> functions when such files (which are expected to be available in the world wide web) get evaluated, and that the information is independent of <strong class="pkg">GAP</strong> –note that <strong class="pkg">MeatAxe</strong> format files and straight line programs can be used by other program systems as well.</p>
</li>
<li><p>The functions <code class="code">ReloadAtlasTableOfContents</code>, <code class="code">StoreAtlasTableOfContents</code>, and <code class="code">ReplaceAtlasTableOfContents</code> are no longer available. They had been intended for updating the table of contents of the <strong class="pkg">ATLAS</strong> of Group Representations, but it has turned out that this was in fact not useful.</p>
</li>
</ul>
<p>The second major change concerns the handling of user parameters.</p>
<ul>
<li><p><strong class="pkg">GAP</strong>'s general <em>user preferences</em> mechanism (see <code class="func">SetUserPreference</code> (<a href="../../../doc/ref/chap3.html#X7B0AD104839B6C3C"><span class="RefLink">Reference: SetUserPreference</span></a>)) has been used since version 1.5.1 of the package for dealing with certain customizations of <strong class="pkg">AtlasRep</strong>'s behaviour, concerning the paths of data directories and two issues with <strong class="pkg">MeatAxe</strong> format files.</p>
<p>Now this mechanism is used in more cases, see Section <a href="chap4.html#X851A50E6810EF8C5"><span class="RefLink">4.2</span></a> for an overview. The new user preferences replace certain components of the record <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap7.html#X7BEC94A6781E126E"><span class="RefLink">7.1-5</span></a>) that were recommended in earlier versions of the package. These components are currently still available but are no longer used by the package's functions. Also the global variable <code class="code">ATLASREP_TOCFILE</code> is no longer supported, use the user preference <code class="code">AtlasRepTOCData</code> instead, see Section <a href="chap4.html#X7F21FFBE7F8108E4"><span class="RefLink">4.2-3</span></a>. Analogously, use the user preference <code class="code">HowToReadMeatAxeTextFiles</code> instead of the no longer available <code class="code">CMeatAxe.FastRead</code>.</p>
<p>The switch to user preferences is an <em>incompatible change</em> if you are used to change the values of these components in your code, for example in your <code class="file">gaprc</code> file, see <a href="../../../doc/ref/chap3.html#X7FD66F977A3B02DF"><span class="RefLink">Reference: The gap.ini and gaprc files</span></a>. All assignments to these components should be changed to calls of <code class="func">SetUserPreference</code> (<a href="../../../doc/ref/chap3.html#X7B0AD104839B6C3C"><span class="RefLink">Reference: SetUserPreference</span></a>).</p>
<p>Another consequence of this change is that the former function <code class="code">AtlasOfGroupRepresentationsUserParameters</code> of the package is no longer supported, use <code class="func">ShowUserPreferences</code> (<a href="../../../doc/ref/chap3.html#X7B0AD104839B6C3C"><span class="RefLink">Reference: ShowUserPreferences</span></a>) or <code class="func">BrowseUserPreferences</code> (<a href="../../../pkg/browse/doc/chap6.html#X7A7B712E7A06449F"><span class="RefLink">Browse: BrowseUserPreferences</span></a>) with argument <code class="code">"AtlasRep"</code> instead.</p>
</li>
</ul>
<p>Finally, the following improvements have been added.</p>
<ul>
<li><p>Straight line programs for computing generators of normal subgroups can now be fetched with <code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>), using the argument <code class="code">"kernel"</code>. The available programs of this type are shown in the <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) overview for a group. More than <span class="SimpleMath">200</span> such programs are available in a new data directory <code class="file">datapkg</code> of the package. If fact, this collection of files is part of an extension of the database that is distributed together with the package.</p>
<p>In earlier versions of the package, this kind of information had been available only implicitly; it had been stored via <code class="code">AGR.KERPRG</code>, which is not supported anymore.</p>
</li>
<li><p><code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>) supports more variants of arguments: <code class="code">"contents"</code> can be used to list the available data extensions, <code class="code">"contents"</code> and <code class="code">"version"</code> can be used to restrict the data under consideration, and one can request a program for computing <em>standard</em> generators of some maximal subgroup, not just generators (provided that this information is available).</p>
<p>The information about the version of straight line programs is shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), as well as the availability of straight line programs for computing standard generators of maximal subgroups.</p>
<p>Making this information more explicit has the side-effect that the access to the <strong class="pkg">AtlasRep</strong> data with <code class="func">BrowseAtlasInfo</code> (<a href="../../../pkg/browse/doc/chap6.html#X8411AF928194C5AB"><span class="RefLink">Browse: BrowseAtlasInfo</span></a>) is both safer and simpler, if at least version 1.8.6 of the <strong class="pkg">Browse</strong> package is available. (For that, the function <code class="code">AGR.InfoPrgs</code> has been extended such that also the <code class="code">identifier</code> records are included in the result.)</p>
</li>
<li><p>Straight line programs for computing <em>standard</em> generators of a maximal subgroup, if available, can now be fetched with <code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>), using the argument <code class="code">"maxstd"</code>.</p>
</li>
<li><p>The function <code class="func">AtlasRepInfoRecord</code> (<a href="chap3.html#X87BC7D9C7BA2F27A"><span class="RefLink">3.5-10</span></a>) now admits a group name as its argument, and then returns information about the group and its maximal subgroups; this information had been used before by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), but it had not been programmatically accessible.</p>
</li>
<li><p>The sanity checks for the data (see Section <a href="chap7.html#X79C5F2267ACCF52A"><span class="RefLink">7.9</span></a>) have been extended, in particular they can be applied also to data extensions. To some extent, these checks can be used also to derive new information; the code for that should be regarded as heuristic and experimental, runtimes and space requirements may be large, depending on the new data to be examined.</p>
</li>
<li><p>Different header formats are now supported when reading and writing <strong class="pkg">MeatAxe</strong> format files, see Section <a href="chap4.html#X7B8F757B85F87936"><span class="RefLink">4.2-8</span></a>, and one can set a global default for the creation of mode 2 <strong class="pkg">MeatAxe</strong> files, see Section <a href="chap4.html#X7941C4378261E28A"><span class="RefLink">4.2-9</span></a>.</p>
</li>
<li><p>The function <code class="func">MeatAxeString</code> (<a href="chap7.html#X7DDD09BE87063052"><span class="RefLink">7.3-2</span></a>) admits also an integer matrix as argument.</p>
</li>
<li><p>The function <code class="func">CMtxBinaryFFMatOrPerm</code> (<a href="chap7.html#X8477AA668733255C"><span class="RefLink">7.3-4</span></a>) admits an optional argument <var class="Arg">base</var>, in order to write <strong class="pkg">MeatAxe</strong> format files that contain either zero based or one based permutations.</p>
</li>
<li><p>The meaningless lines about <span class="SimpleMath">p</span>-modular representations of groups with nontrivial <span class="SimpleMath">p</span>-core have been removed from the file <code class="file">gap/mindeg.g</code>.</p>
</li>
</ul>
<p><a id="X7EACAC887E257302" name="X7EACAC887E257302"></a></p>
<h5>1.3-11 <span class="Heading">What's New in Version 1.5.1? (March 2016)</span></h5>
<ul>
<li><p>The paths of the directories where downloaded data files get stored are now customizable, see Section <a href="chap4.html#X7C36E9A78021A71A"><span class="RefLink">4.2-2</span></a>. Up to now, the data were stored in subdirectories of the package directory, which might cause problems with write permissions, depending on the installation of the package. (Note that choosing other data directories can be useful also in order to keep existing local data files when a new version of <strong class="pkg">GAP</strong> or of the <strong class="pkg">AtlasRep</strong> package gets installed.) Thanks to Bill Allombert for pointing out this problem.</p>
</li>
<li><p>The information about data files from the <strong class="pkg">ATLAS</strong> of Group Representations has been extended by <code class="func">CrcFile</code> (<a href="../../../doc/ref/chap9.html#X8241CEAD80415BB9"><span class="RefLink">Reference: CrcFile</span></a>) values. These values are checked whenever data from such a file are read, and an error is signalled if the checksum does not fit to the expected one. Note that several users may access the same data files, and a user should not suffer from perhaps corrupted files that have been downloaded by other users. Thanks to Frank Lübeck for the idea to introduce this consistency test.</p>
</li>
<li><p>Whenever <code class="func">StringFile</code> (<a href="../../../pkg/gapdoc/doc/chap6.html#X7E14D32181FBC3C3"><span class="RefLink">GAPDoc: StringFile</span></a>) is called by functions of the package, this happens in the wrapper function <code class="code">AGR.StringFile</code>, in order to replace occasional line breaks of the form <code class="code">"\r\n"</code> by <code class="code">"\n"</code>. Apparently it may happen that the <code class="code">"\r"</code> is silently smuggled in when data files get copied to the local computer. Thanks to Marek Mitros for help with detecting and fixing this problem.</p>
</li>
<li><p>The function <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap7.html#X872FA00C7F791FBB"><span class="RefLink">7.3-5</span></a>) can now read also permutations stored in binary files that have been created with version 2.4 of the C-<strong class="pkg">MeatAxe</strong>; note that this format is different from the one that is written by version 2.3. Conversely, <code class="func">CMtxBinaryFFMatOrPerm</code> (<a href="chap7.html#X8477AA668733255C"><span class="RefLink">7.3-4</span></a>) has been generalized such that both formats can be written. The reference to the C-<strong class="pkg">MeatAxe</strong> documentation now points to that of version 2.4. Thanks to Jürgen Müller for pointing out this problem.</p>
</li>
<li><p>The function <code class="func">MeatAxeString</code> (<a href="chap7.html#X7DDD09BE87063052"><span class="RefLink">7.3-2</span></a>) can now encode permutation matrices in different ways. The mode (the first header entry) can be either 2 (then the positions of the nonzero entries are listed) or 1 or 6 (then all entries of the matrix are listed). In previous versions, the function produced a matrix of mode 2 whenever this was possible, but this behaviour is not useful if the result is not processed by the C-<strong class="pkg">MeatAxe</strong>. Thanks to Klaus Lux for pointing out this problem.</p>
</li>
<li><p>Depending on the terminal capabilities and the user preference <code class="code">DisplayFunction</code> (see <a href="chap4.html#X81F055037F9D3068"><span class="RefLink">4.2-11</span></a>), some non-ASCII characters may appear in the output shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>).</p>
</li>
</ul>
<p><a id="X86002B747AE0741B" name="X86002B747AE0741B"></a></p>
<h5>1.3-12 <span class="Heading">What's New in Version 1.5? (July 2011)</span></h5>
<ul>
<li><p>The function <code class="func">AtlasSubgroup</code> (<a href="chap3.html#X7A3E460C82B3D9A3"><span class="RefLink">3.5-9</span></a>) now admits also the return value of <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) or the return value of <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>) as its first argument. The latter is implemented via the new attribute <code class="func">AtlasRepInfoRecord</code> (<a href="chap3.html#X87BC7D9C7BA2F27A"><span class="RefLink">3.5-10</span></a>), which is set in the groups constructed by <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>).</p>
</li>
<li><p>Information about transitivity, rank, primitivity, and point stabilizers of many permutation representations is now available. If applicable then this information appears in the records returned by <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), it is part of the overview shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), and it is shown also in the data overview in the web, see Section <a href="chap4.html#X7C50F18587ADC3B5"><span class="RefLink">4.3</span></a>.</p>
<p>Two new manual sections about point stabilizers have been added, see the sections <a href="chap2.html#X82550A9683E0DCA2"><span class="RefLink">2.4-6</span></a> and <a href="chap2.html#X84F9D163795B7DE1"><span class="RefLink">2.4-7</span></a>.</p>
</li>
<li><p>Information about the characters afforded by many matrix and permutation representations is now available. If applicable then this information appears in the records returned by <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), for matrix representations it is part of the overview shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), and it is shown also in the data overview in the web, see Section <a href="chap4.html#X7C50F18587ADC3B5"><span class="RefLink">4.3</span></a>.</p>
</li>
<li><p>The functions <code class="func">Character</code> (<a href="../../../doc/ref/chap72.html#X849DD34C7968206C"><span class="RefLink">Reference: Character for a character table and a list</span></a>), <code class="func">Identifier</code> (<a href="../../../doc/ref/chap71.html#X79C40EE97890202F"><span class="RefLink">Reference: Identifier for character tables</span></a>), <code class="func">IsPrimitive</code> (<a href="../../../doc/ref/chap41.html#X84C19AD68247B760"><span class="RefLink">Reference: IsPrimitive</span></a>), <code class="func">IsTransitive</code> (<a href="../../../doc/ref/chap41.html#X79B15750851828CB"><span class="RefLink">Reference: IsTransitive</span></a>), <code class="func">Transitivity</code> (<a href="../../../doc/ref/chap41.html#X8295D733796B7A37"><span class="RefLink">Reference: Transitivity</span></a>), and <code class="func">RankAction</code> (<a href="../../../doc/ref/chap41.html#X8166A6A17C8D6E73"><span class="RefLink">Reference: RankAction</span></a>) are now supported as input conditions in <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) and <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>).</p>
</li>
<li><p>It is now possible to restrict the data shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) or returned by <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) to private or non-private data.</p>
</li>
<li><p>A tutorial for beginners was added to the manual, see Chapter <a href="chap2.html#X8171B3798425E183"><span class="RefLink">2</span></a>, and the manual was restructured.</p>
</li>
<li><p>In the overview shown by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) and in the data overview in the web (see Section <a href="chap4.html#X7C50F18587ADC3B5"><span class="RefLink">4.3</span></a>), the ordering of groups was improved such that, e.g., <code class="code">"A9"</code> precedes <code class="code">"A10"</code>.</p>
</li>
<li><p>The function <code class="func">AtlasClassNames</code> (<a href="chap3.html#X78166D1D7D18EFBF"><span class="RefLink">3.4-2</span></a>) now admits also a Brauer table as its argument, and works also for character tables of bicyclic extensions of simple groups.</p>
</li>
<li><p>The group names that are entered in <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), etc., are now case insensitive, and if the package <strong class="pkg">CTblLib</strong> is available then the admissible group names for the <strong class="pkg">GAP</strong> character table of the group in question can be used in these functions.</p>
</li>
<li><p>In order to reduce the number of global variables, several functions have been turned into components of the new global variable <code class="func">AGR</code> (<a href="chap7.html#X84A157BF7D0CB270"><span class="RefLink">7.1-4</span></a>). A few of these functions had been documented in the previous version, the old values are still available if the package files <code class="file">gap/obsolete.gd</code> and <code class="file">gap/obsolete.gi</code> have been read. These files are read automatically if <strong class="pkg">GAP</strong>'s user preference <code class="code">"ReadObsolete"</code> is <code class="keyw">true</code> when the package gets loaded, see <a href="../../../doc/ref/chap3.html#X87DF11C885E73583"><span class="RefLink">Reference: The gap.ini file</span></a>.</p>
</li>
<li><p>A few nicer characters are used by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) if <code class="code">GAPInfo.TermEncoding</code> has the value <code class="code">"UTF-8"</code> and if <code class="func">Print</code> (<a href="../../../doc/ref/chap6.html#X7AFA64D97A1F39A3"><span class="RefLink">Reference: Print</span></a>) is not the display function to be used, see Section <a href="chap4.html#X81F055037F9D3068"><span class="RefLink">4.2-11</span></a>.</p>
</li>
<li><p>A bug in the function <code class="code">ReloadAtlasTableOfContents</code> was fixed. Thanks to Jack Schmidt for reporting this bug.</p>
</li>
</ul>
<p><a id="X878EBA108716DDF0" name="X878EBA108716DDF0"></a></p>
<h5>1.3-13 <span class="Heading">What's New in Version 1.4? (June 2008)</span></h5>
<ul>
<li><p>In addition to the group orders that were added in version 1.3 (see Section <a href="chap1.html#X79CCC5517897924C"><span class="RefLink">1.3-15</span></a>), also many orders of maximal subgroups are now available. These values occur in the records returned by <code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>) (for the case of <code class="code">"maxes"</code> type programs) and of the three argument version of <code class="func">AtlasGenerators</code> (<a href="chap3.html#X7D1CCCF8852DFF39"><span class="RefLink">3.5-3</span></a>); now a <code class="code">size</code> component may be bound. In these cases, the groups returned by <code class="func">AtlasSubgroup</code> (<a href="chap3.html#X7A3E460C82B3D9A3"><span class="RefLink">3.5-9</span></a>) have the <code class="func">Size</code> (<a href="../../../doc/ref/chap30.html#X858ADA3B7A684421"><span class="RefLink">Reference: Size</span></a>) attribute set.</p>
</li>
<li><p>The information about the number of maximal subgroups, if available, is now used in <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>).</p>
</li>
<li><p>In many cases, straight line programs for computing generators of maximal subgroups of a group <span class="SimpleMath">G</span>, say, can in fact be used to compute also generators of maximal subgroups of downward extensions of <span class="SimpleMath">G</span>; if not then it may suffice to extend the given straight line programs by additional generators.</p>
<p>Currently this yields more than <span class="SimpleMath">200</span> new possibilities to compute maximal subgroups, this means a growth by about <span class="SimpleMath">25</span> percent. For example, all maximal subgroups of <span class="SimpleMath">12.M_22</span> and <span class="SimpleMath">2.Fi_22</span> can now be accessed via <code class="func">AtlasGenerators</code> (<a href="chap3.html#X7D1CCCF8852DFF39"><span class="RefLink">3.5-3</span></a>).</p>
<p>(Of course this extension means only that one can access the straight line programs in question automatically via the <strong class="pkg">GAP</strong> interface. In principle one could have used them already before, by explicitly applying a straight line program for a factor group to generators of a group, and perhaps adding some element in the kernel of the natural epimorphism.)</p>
<p>For this feature, information about the compatibility of standard generators of groups and their factor groups was added.</p>
</li>
<li><p>The bibliographies contained in the <strong class="pkg">ATLAS</strong> of Finite Groups <a href="chapBib.html#biBCCN85">[CCN+85]</a> and in the <strong class="pkg">ATLAS</strong> of Brauer Characters <a href="chapBib.html#biBJLPW95">[JLPW95]</a> are now available as HTML files, as BibXMLext files, and within <strong class="pkg">GAP</strong>, see <code class="func">BrowseBibliographySporadicSimple</code> (<a href="chap3.html#X84ED4FC182C28198"><span class="RefLink">3.6-2</span></a>).</p>
</li>
<li><p>If the <strong class="pkg">GAP</strong> package <strong class="pkg">Browse</strong> (see <a href="chapBib.html#biBBrowse">[BL18]</a>) is loaded then the new functions <code class="func">BrowseMinimalDegrees</code> (<a href="chap3.html#X7F31A7CB841FE63F"><span class="RefLink">3.6-1</span></a>) and <code class="func">BrowseBibliographySporadicSimple</code> (<a href="chap3.html#X84ED4FC182C28198"><span class="RefLink">3.6-2</span></a>) are available; these functions can be called also by choosing the corresponding menu entries of the <strong class="pkg">Browse</strong> application <code class="func">BrowseGapData</code> (<a href="../../../pkg/browse/doc/chap6.html#X850C786C87A4877B"><span class="RefLink">Browse: BrowseGapData</span></a>).</p>
</li>
<li><p>The function <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>) now admits also the return value of <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) as its argument.</p>
</li>
</ul>
<p><a id="X87A53CE182C9E086" name="X87A53CE182C9E086"></a></p>
<h5>1.3-14 <span class="Heading">What's New in Version 1.3.1? (October 2007)</span></h5>
<p>This version was mainly released in order to fix a few problems. Now one does not get warnings about unbound variables when the package is loaded and the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu14]</a> is not available, and pathological situations in <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap7.html#X872FA00C7F791FBB"><span class="RefLink">7.3-5</span></a>) (concerning extremely short corrupted data files and different byte orderings in binary files) are handled more carefully.</p>
<p>Besides this, the two functions <code class="func">AtlasGroup</code> (<a href="chap3.html#X80AABEE783363B70"><span class="RefLink">3.5-8</span></a>) and <code class="func">AtlasSubgroup</code> (<a href="chap3.html#X7A3E460C82B3D9A3"><span class="RefLink">3.5-9</span></a>) were introduced, and the extended function <code class="func">QuaternionAlgebra</code> (<a href="../../../doc/ref/chap62.html#X83DF4BCC7CE494FC"><span class="RefLink">Reference: QuaternionAlgebra</span></a>) of <strong class="pkg">GAP</strong> 4.4.10 can now be used for describing base rings in <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>). (This is the reason why this version of the package requires at least version 4.4.10 of <strong class="pkg">GAP</strong>.)</p>
<p><a id="X79CCC5517897924C" name="X79CCC5517897924C"></a></p>
<h5>1.3-15 <span class="Heading">What's New in Version 1.3? (June 2007)</span></h5>
<ul>
<li><p>The database was extended, see Section <a href="chap4.html#X8766BE5D7AD6C526"><span class="RefLink">4.2-4</span></a> for the number and size of files.</p>
</li>
<li><p>New data types and corresponding <strong class="pkg">GAP</strong> objects have been introduced, for representing semi-presentations, presentations, and programs for finding standard generators. For details, see <code class="func">AtlasProgram</code> (<a href="chap3.html#X801F2E657C8A79ED"><span class="RefLink">3.5-4</span></a>), Chapter <a href="chap6.html#X83827EDB7D36C407"><span class="RefLink">6</span></a>, and Section <a href="chap7.html#X7A86627B80980F61"><span class="RefLink">7.6</span></a>.</p>
</li>
<li><p>The records returned by the functions <code class="func">AtlasGenerators</code> (<a href="chap3.html#X7D1CCCF8852DFF39"><span class="RefLink">3.5-3</span></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>) now contain the name and (if known) the order of the group in question, and also components describing the degree in the case of permutation representations or the dimension and the base ring of the natural module in the case of matrix representations.</p>
</li>
<li><p>For many of the groups, information about the minimal degree of faithful permutation representations and the minimal dimensions of faithful matrix representations in various characteristics is available for <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>), see also Section <a href="chap6.html#X87E1F08D80C9E069"><span class="RefLink">6.3</span></a>. For these functions, also properties such as <code class="func">IsPrimeInt</code> (<a href="../../../doc/ref/chap14.html#X78FDA4437EDCA70C"><span class="RefLink">Reference: IsPrimeInt</span></a>) can be used to describe the intended restriction of the output.</p>
</li>
<li><p>One can now use <code class="func">Pager</code> (<a href="../../../doc/ref/chap2.html#X7ED03E41792C3840"><span class="RefLink">Reference: Pager</span></a>) functionality in <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), see Section <a href="chap4.html#X81F055037F9D3068"><span class="RefLink">4.2-11</span></a>.</p>
<p>An interactive alternative to <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>) is provided by the function <code class="func">BrowseAtlasInfo</code> (<a href="../../../pkg/browse/doc/chap6.html#X8411AF928194C5AB"><span class="RefLink">Browse: BrowseAtlasInfo</span></a>) from the new (recommended) <strong class="pkg">GAP</strong> package <strong class="pkg">Browse</strong> (see <a href="chapBib.html#biBBrowse">[BL18]</a>).</p>
</li>
<li><p>The functions <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>) now admit also a list of group names as the first argument.</p>
</li>
<li><p>The functions for actually accessing the data are more flexible now, see Section <a href="chap7.html#X81C5B5E78215169D"><span class="RefLink">7.2</span></a>.</p>
</li>
<li><p>For transferring remote data, the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> (see <a href="chapBib.html#biBIO">[Neu14]</a>) can now be used (and is recommended) as an alternative to <code class="file">wget</code>.</p>
</li>
<li><p>The address of the data server has changed. The access to the server is no longer possible via <code class="file">ftp</code>, thus the mechanism used up to version 1.2, which was based on <code class="file">ftp</code>, had to be rewritten.</p>
<p>The main consequence of this change is that information about updates of the table of contents is now provided at the package's homepage. This means that on the one hand, now package users cannot <em>compute</em> the table of contents directly from the server data, but on the other hand the update information can be <em>downloaded</em> without the necessity to install <code class="file">perl</code>.</p>
<p>Another consequence is that the system program <code class="file">ls</code> is no longer needed, see Section <a href="chap1.html#X831628B47F669B29"><span class="RefLink">1.3-17</span></a>.</p>
</li>
<li><p>The package manual has been restructured, extended and improved. It is now based on the package <strong class="pkg">GAPDoc</strong> (see <a href="chapBib.html#biBGAPDoc">[LN18]</a>).</p>
</li>
</ul>
<p><a id="X7BDCA94D83DCFFB8" name="X7BDCA94D83DCFFB8"></a></p>
<h5>1.3-16 <span class="Heading">What's New in Version 1.2? (November 2003)</span></h5>
<p>Not much.</p>
<p>The release of Version 1.2 became necessary first of all in order to provide a package version that is compatible with <strong class="pkg">GAP</strong> 4.4, since some cross-references into the <strong class="pkg">GAP</strong> Reference Manual were broken due to changes of section names. Additionally, several web addresses concerning the package itself were changed and thus had to be adjusted.</p>
<p>This opportunity was used</p>
<ul>
<li><p>to upgrade the administrational part for loading the package to the mechanism that is recommended for <strong class="pkg">GAP</strong> 4.4,</p>
</li>
<li><p>to extend the test suite, which now covers more consistency checks using the <strong class="pkg">GAP</strong> Character Table Library (see <a href="chapBib.html#biBCTblLib">[Bre22]</a>),</p>
</li>
<li><p>to make the function <code class="func">ScanMeatAxeFile</code> (<a href="chap7.html#X83D5103780E1238F"><span class="RefLink">7.3-1</span></a>) more robust, due to the fact that the <strong class="pkg">GAP</strong> function <code class="func">PermList</code> (<a href="../../../doc/ref/chap42.html#X78D611D17EA6E3BC"><span class="RefLink">Reference: PermList</span></a>) now returns <code class="keyw">fail</code> instead of raising an error,</p>
</li>
<li><p>to change the way how representations with prescribed properties are accessed (the new function <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>) is now preferred to the former <code class="code">OneAtlasGeneratingSet</code>, and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>) has been added in order to provide programmatic access in parallel to the human readable descriptions printed by <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>)),</p>
</li>
<li><p>and last but not least to include the current table of contents of the underlying database.</p>
</li>
</ul>
<p>For <strong class="pkg">AtlasRep</strong> users, the new feature of <strong class="pkg">GAP</strong> 4.4 is particularly interesting that due to better kernel support, reading large matrices over finite fields is now faster than it was in <strong class="pkg">GAP</strong> 4.3.</p>
<p><a id="X831628B47F669B29" name="X831628B47F669B29"></a></p>
<h5>1.3-17 <span class="Heading">What's New in Version 1.1? (October 2002)</span></h5>
<p>The biggest change w. r. t. Version 1.1 is the addition of private extensions (see Chapter <a href="chap5.html#X7B0718A178BB10CA"><span class="RefLink">5</span></a>). It includes a new <q>free format</q> for straight line programs (see Section <a href="chap5.html#X7A6024EC87A95E0B"><span class="RefLink">5.2</span></a>). Unfortunately, this feature requires the system program <code class="file">ls</code>, so it may be not available for example under MS Windows operating systems. [But see Section <a href="chap1.html#X79CCC5517897924C"><span class="RefLink">1.3-15</span></a>.]</p>
<p>In order to admit the addition of other types of data, the implementation of several functions has been changed. Data types are described in Section <a href="chap7.html#X809898027EFDA56E"><span class="RefLink">7.5</span></a>. An example of a new data type are quaternionic representations (see Section <a href="chap7.html#X7A86627B80980F61"><span class="RefLink">7.6</span></a>). The user interface itself (see Chapter <a href="chap3.html#X87EAF8E578D95793"><span class="RefLink">3</span></a>) remained the same.</p>
<p>As an alternative to <code class="code">perl</code>, one can use <code class="code">wget</code> now for transferring data files (see <a href="chap4.html#X851A50E6810EF8C5"><span class="RefLink">4.2</span></a>).</p>
<p>Data files can be read much more efficiently in <strong class="pkg">GAP</strong> 4.3 than in <strong class="pkg">GAP</strong> 4.2. In Version 1.1 of the <strong class="pkg">AtlasRep</strong> package, this feature is used for reading matrices and permutations in <strong class="pkg">MeatAxe</strong> text format with <code class="func">ScanMeatAxeFile</code> (<a href="chap7.html#X83D5103780E1238F"><span class="RefLink">7.3-1</span></a>). As a consequence, (at least) <strong class="pkg">GAP</strong> 4.3 is required for <strong class="pkg">AtlasRep</strong> Version 1.1.</p>
<p>The new <code class="code">compress</code> component of the global variable <code class="func">AtlasOfGroupRepresentationsInfo</code> (<a href="chap7.html#X7BEC94A6781E126E"><span class="RefLink">7.1-5</span></a>) allows one to store data files automatically in <code class="file">gzip</code>ped form.</p>
<p>For matrix representations in characteristic zero, invariant forms and generators for the centralizer algebra are now accessible in <strong class="pkg">GAP</strong> if they are contained in the source files –this information had been ignored in Version 1.0.</p>
<p>Additional information is now available via the internet (see <a href="chap4.html#X7C50F18587ADC3B5"><span class="RefLink">4.3</span></a>).</p>
<p>The facilities for updating the table of contents have been extended.</p>
<p>The manual is now distributed also in PDF and HTML format; on the other hand, the PostScript format manual is no longer contained in the archives.</p>
<p>Apart from these changes, a few minor bugs in the handling of <strong class="pkg">MeatAxe</strong> files have been fixed, typos in the documentation have been corrected, and the syntax checks for <strong class="pkg">ATLAS</strong> straight line programs (see <a href="chap7.html#X7FEE162B7F63BEA0"><span class="RefLink">7.4</span></a>) have been improved.</p>
<p><a id="X82A988D47DFAFCFA" name="X82A988D47DFAFCFA"></a></p>
<h4>1.4 <span class="Heading">Acknowledgements</span></h4>
<ul>
<li><p>Frank Lübeck and Max Neunhöffer kindly provided the perl script that had been used for fetching remote data until version 1.2. Thanks also to Greg Gamble and Alexander Hulpke for technical hints concerning <q>standard</q> perl.</p>
</li>
<li><p>Ulrich Kaiser helped with preparing the package for MS Windows.</p>
</li>
<li><p>Klaus Lux had the idea to support data extensions, see Chapter <a href="chap5.html#X7B0718A178BB10CA"><span class="RefLink">5</span></a>, he did a lot of beta testing, and helped to fix several bugs.</p>
</li>
<li><p>Frank Lübeck contributed the functions <code class="func">CMtxBinaryFFMatOrPerm</code> (<a href="chap7.html#X8477AA668733255C"><span class="RefLink">7.3-4</span></a>) and <code class="func">FFMatOrPermCMtxBinary</code> (<a href="chap7.html#X872FA00C7F791FBB"><span class="RefLink">7.3-5</span></a>).</p>
</li>
<li><p>Frank Lübeck and Max Neunhöffer wrote the <strong class="pkg">GAPDoc</strong> package <a href="chapBib.html#biBGAPDoc">[LN18]</a>, which is used for processing the documentation of the <strong class="pkg">AtlasRep</strong> package and for processing the bibliographies included in this package (see <code class="func">BrowseBibliographySporadicSimple</code> (<a href="chap3.html#X84ED4FC182C28198"><span class="RefLink">3.6-2</span></a>)),</p>
</li>
<li><p>Max Neunhöffer wrote the <strong class="pkg">GAP</strong> package <strong class="pkg">IO</strong> <a href="chapBib.html#biBIO">[Neu14]</a>, which is recommended for transferring data.</p>
</li>
<li><p>Max Neunhöffer has also suggested the generalization of the data access described in Section <a href="chap7.html#X81C5B5E78215169D"><span class="RefLink">7.2</span></a>, the admissibility of the function <code class="func">Character</code> (<a href="../../../doc/ref/chap72.html#X849DD34C7968206C"><span class="RefLink">Reference: Character for a character table and a list</span></a>) as a filter in <code class="func">DisplayAtlasInfo</code> (<a href="chap3.html#X79DACFFA7E2D1A99"><span class="RefLink">3.5-1</span></a>), <code class="func">OneAtlasGeneratingSetInfo</code> (<a href="chap3.html#X841478AB7CD06D44"><span class="RefLink">3.5-6</span></a>), and <code class="func">AllAtlasGeneratingSetInfos</code> (<a href="chap3.html#X84C2D76482E60E42"><span class="RefLink">3.5-7</span></a>), and the variant of <code class="func">AtlasRepInfoRecord</code> (<a href="chap3.html#X87BC7D9C7BA2F27A"><span class="RefLink">3.5-10</span></a>) that takes a group name as its input.</p>
</li>
<li><p>Gunter Malle suggested to make the information about representations of minimal degree accessible, see Section <a href="chap6.html#X87E1F08D80C9E069"><span class="RefLink">6.3</span></a>.</p>
</li>
<li><p>Andries Brouwer suggested to add a tutorial (see Chapter <a href="chap2.html#X8171B3798425E183"><span class="RefLink">2</span></a>), Klaus Lux suggested several improvements of this chapter.</p>
</li>
<li><p>The development of this <strong class="pkg">GAP</strong> package has been supported by the <span class="URL"><a href="https://www.computeralgebra.de/sfb/">SFB-TRR 195 <q>Symbolic Tools in Mathematics and their Applications</q></a></span> (from 2017 until 2022).</p>
</li>
</ul>
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