1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
% There's no easy way to generate equation numbers like (1a), (1b), (1') etc.
% However these are both easily fixed by reading in eqalign.sty (via the
% optional arg to \documentstyle) where eqalign.sty contains:
% eqalign (style option for all styles) to re-enable PLAIN TeX's
% \eqalign command and generalize the LaTeX's equation numbering.
% Written by Charles Karney (Karney%PPC.MFENET@NMFECC.ARPA) 1986/01/03.
% This style option can be used with any style. E.g.,
% \documentstyle[11pt,eqalign]{article}
% It provides:
% (1) \eqalign, \displaylines, \eqalignno, and \leqalignno from Plain
% TeX.
% (2) \eqn(A5c) gives \eqno\hbox{(A5c)}. This ensures that the "A" and
% "c" are set in Roman.
% (3) \eqnum increments the equation counter and prints it. E.g.,
% $$x^2+y^2=z^2, \eqn(\eqnum)$$
% (4) \eqlab{<label>} is the same as \eqnum except that \ref{<label>} can
% be used to refer to the equation. E.g.,
% $$x^2+y^2=z^2, \eqn(\eqlab{Pythag})$$
% ... as is shown in Eq.~(\ref{Pythag}). ...
% (5) \eqlab and \ref in combination allow the inclusion of alphabetic
% suffices to equation numbers. E.g.,
% $$\eqalignno{
% a&=b+c, &(\eqlab{triv}a)\cr % gives (10a)
% d&=e+f, &(\ref{triv}b)\cr % gives (10b)
% g&=h+i. &(\ref{triv}c)\cr}$$ % gives (10c)
% ... as is shown in Eq.~(\ref{triv}a) ...
% ... as is shown in Eqs.~(\ref{triv}) ...
% and so on.
\def\eqalign#1{\null\,\vcenter{\openup\jot\m@th
\ialign{\strut\hfil$\displaystyle{##}$&$\displaystyle{{}##}$\hfil
\crcr#1\crcr}}\,}
\def\@lign{\tabskip\z@skip\everycr{}} % restore inside \displ@y
\def\displaylines#1{\displ@y
\halign{\hbox to\displaywidth{$\@lign\hfil\displaystyle##\hfil$}\crcr
#1\crcr}}
\def\eqalignno#1{\displ@y \tabskip\@centering
\halign to\displaywidth{\hfil$\@lign\displaystyle{##}$\tabskip\z@skip
&$\@lign\displaystyle{{}##}$\hfil\tabskip\@centering
&\llap{$\@lign\hbox{##}$}\tabskip\z@skip\crcr
#1\crcr}}
\def\leqalignno#1{\displ@y \tabskip\@centering
\halign to\displaywidth{\hfil$\@lign\displaystyle{##}$\tabskip\z@skip
&$\@lign\displaystyle{{}##}$\hfil\tabskip\@centering
&\kern-\displaywidth\rlap{$\@lign\hbox{##}$}\tabskip\displaywidth\crcr
#1\crcr}}
\def\eqn(#1){\eqno\hbox{(#1)}}
\def\eqnum{{\refstepcounter{equation}\theequation}}
\def\eqlab#1{{\refstepcounter{equation}\label{#1}\theequation}}
|
