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Change Log 01/11/2002
=====================================================================
Version 4.1.1 beta (01/11/2002) Major Changes:
- Database added. Now it is possible to store examples of groups and
their descriptions in the Database as well as save and rstore objects
in the Workspace.
- Package Mechanism. MAGNUS' Package Mechanism was developed to provide
a simple and convenient way of integrating second party software into
MAGNUS' graphical user interface. See doc/PackagesManual.ps for more
details.
- MAGNUS' menus were changed
- Random definitions when cheking in objects are available.
- George Havas' version of Todd-Coxeter procedure is incorporated.
- Lots of new procedures for almost every type of groups are added.
- lots of bugs fixed.
=====================================================================
Version 3.2.1 pre-release(11/24/99) Major Changes:
- Source code is compliant with the recent version of C++ draft and
can be compiled by egcs-1.1.2 - the version of GNU compiler included
in Linux 6.0 and 6.1 disrtibutions.
- Class templates implementation is simplified, so that it is easier
to compile Magnus under different platforms.
- New genetic algorithms for:
* Whitehead reduction for tuples of words in a free group.
* Andrews-Curtis reduction for tuples of words in a free group.
* Solving equations in a free group.
- New version of Todd-Coxeter procedure.
- New word problem sover for free nilpotent groups (using power series).
- Lots of bugs fixed.
======================================================================
Version 3.0.0 pre-release(10/14/98) Changes and Enhancements:
- Fixed bug in Subgroup List Algorithm.
=====================================================================
Version 2.9.8 pre-release(09/19/98) Changes and Enhancements:
- New algorithms for free groups:
* For group F and word W:
- Genetic algorithm for solving problem "Is word part of a basis?".
- Genetic algorithm for solving product of two commutators problem.
- For group F and a tuple T of words:
* Genetic algorithm to carry out Andrews-Curtis reduction.
- For group F, subgroup H and word W in H:
* Express an element of a subgroup in terms of the subgroup
generators(details will be provided by a link to a file).
- New algorithms for one relator groups:
* For one relator group G and word W:
* Word problem(details will be provided by a link to a file).
* "Express word in conjugates of relators?".
- Dehn's algorithm for metric small cancellation groups:
*A link has been added to show details of the computation.
- For all but nilpotent and abelian groups, two new algorithms have been added :
* "Re-write word as a product of commutators".
* "Rewrite word as a product of squares".
- For a finitely presented group G and a subgroup H of finite index,
there is a new algorithm:
* "Rewrite W in terms of Schrier generators of H".
======================================================================
Version 2.9.0 pre-release(04/18/98) Changes and Enhancements:
- New genetic algorithms for finitely presented groups:
For group G:
* Is G trivial?
* Is G abelian?
For words w, w1, w2:
* Is w central?
* Is w1 = w2?
For subgroup H:
* Is H trivial?
* Is H abelian?
* Is H central?
For map m:
* Does m extend to a homomorphism?
- Many reported bugs are now fixed.
- New kinds of objects "Enumerators" and "Lists" were added:
* Word enumerator.
* Relator enumerator.
* Automorphisms enumerator for free groups.
* Relator enumerator for a subgroup.
* Make a list of words from an enumerator.
- Tools for lists:
* Find a word in a list.
* Extract all words from the defined length range.
==========================================================================
Version 2.8.4 pre-release(02/13/98) Changes and Enhancements:
- Magnus menus now change dynamically to reflect the information found
about objects. For example, if a group is found to be abelian then the
menu for it will change, so that new "abelian" algorithms are
accessible.
- Existing genetic algorithms for finitely presented groups (word problem,
triviality problem, "is a group abelian ?" problem) and for solving equations
in a free group were modified to show better performance.
- Many message misprints were corrected.
- New pages were added to the magnus manual. Many broken links were
fixed.
- The description of the format used for a finite state automaton is now
available.
- Magnus manual and workspace manual work on every supported system now.
- As of now, Linux 5.0 and Tcl/Tk 8.0 are fully supported. Magnus
compiles and runs cleanly.
- For now, "Is Finite" and "Order" problems for FP groups
are identical. This means that both use all related fast checks and
algorithms to solve the problem. This situation will change.
- One may now compute the conjugate of one word by another.
- One may now compute the length of a word in freely reduced form.
- One may now compute the commutator of two words.
=============================================================================
Version 2.8.0 pre-release(01/08/98) Changes and Enhancements:
- The genetic algorithm for solving the word problem in a finitely presented
group has been optimized.
- Computational details for the Nielsen basis for a subgroup of a free group
have been added.
- Some bugs have been fixed in the algorithm for solving quadratic equations
over a free group.
- For one-relator groups found to have torsion, we have added the following
algorithms:
* A word which is trivial in the given group is re-expressed as a
product of conjugates of the defining relator (and its inverse).
* A word which represents an element of finite order is re-expressed
as a conjugate of a power of r, where here r^n is the given defining
relator.
* A process which enumerates all consequences of the given defining
relator.
- A process which enumerates all of the relations that are satisfied by the
given
generators of a finitely generated subgroup of a finitely presented roup.
==============================================================================
Version 2.7.8 pre-release(12/04/97) Changes and Enhancements:
- Genetic algorithm for the word problem.
- Genetic algorithm for the triviality problem.
- Genetic algorithm for the abelian problem.
- Genetic algorithm for solving equations over a free group.
- Find a permutation representation of G on the cosets of H in G.
- Compute the Schreier representative of an element of G.
- Compute a Schreier transversal of H in G.
- Changed file viewer to eliminate delay in viewing large files in the User
Interface.
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