以下代码无法在 tex4ebook 下编译：
\documentclass{amsart}
\newcommand\Tag[1]{}
\begin{document}
\begin{equation}
x=y\label{t1}\Tag{(*)}
\end{equation}
Look at equation \ref{t1}.
\end{document}
它当然可以在 pdflatex 下编译。（我发现了一个关于自定义的问题\Tag。最后我发现它甚至对空命令不起作用）
答案1
\Tag是用于交叉引用处理的内部 TeX4ht 命令，因此无法重新定义它，否则会破坏很多东西。不同的名称起作用：
% https://tex.stackexchange.com/q/520377/2891
\documentclass{amsart}
\newcommand\myTag[1]{\tag*{#1}}
\begin{document}
\begin{equation}
x=y\label{t1}\myTag{(*)}
\end{equation}
Look at equation \ref{t1}.
\end{document}
似乎\tag*支持存在问题，导致标签打印两次（一次由 Amsmath 打印，然后由 TeX4ht 打印）。我们可以使用以下版本禁用第二次打印amsmath.4ht（我已经更新了源代码，因此它应该很快就会在 TL 中可用）：
% amsmath.4ht (2019-12-16-10:18), generated from tex4ht-4ht.tex
% Copyright 1997-2009 Eitan M. Gurari
% Copyright 2009-2019 TeX Users Group
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either
% version 1.3c of this license or (at your option) any
% later version. The latest version of this license is in
% http://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions
% of LaTeX version 2005/12/01 or later.
%
% This work has the LPPL maintenance status "maintained".
%
% The Current Maintainer of this work
% is the TeX4ht Project <http://tug.org/tex4ht>.
%
% If you modify this program, changing the
% version identification would be appreciated.
\immediate\write-1{version 2019-12-16-10:18}
\HRestore\cases
\HRestore\matrix
\HRestore\pmatrix
\append:def\a:display{\@displaytrue}
\expandafter\append:defIII\csname
c:$$:\endcsname{\append:def\a:display{\@displaytrue}}
\def\above:tbinom#1#2#3#4{\a:tbinom}
\def\:temp{%
\expandafter \ifx\csname a:tbinom\endcsname\relax \else
\ifx\a:tbinom\empty \else
\Configure{abovewithdelims}{\above:tbinom}{}%
\fi\fi
\o:tbinom:}
\HLet\tbinom\:temp
\NewConfigure{tbinom}{1}
\def\above:dbinom#1#2#3#4{\a:dbinom}
\def\:temp{%
\expandafter \ifx\csname a:dbinom\endcsname\relax \else
\ifx\a:dbinom\empty \else
\Configure{abovewithdelims}{\above:dbinom}{}%
\fi\fi
\o:dbinom:}
\HLet\dbinom\:temp
\NewConfigure{dbinom}{1}
\def\above:binom#1#2#3#4{\a:binom}
\def\:temp#1{%
\def\:temp{%
\expandafter \ifx\csname a:binom\endcsname\relax \else
\ifx\a:binom\empty \else
\Configure{abovewithdelims}{\above:binom}{}%
\fi\fi
#1}}
\expandafter\:temp\expandafter{\csname o:binom :\endcsname}
\expandafter\HLet\csname binom \endcsname\:temp
\NewConfigure{binom}{1}
\pend:def\subequations{\SkipRefstepAnchor }
\def\hdots@for#1#2{\multicolumn{#2}c%
{\m@th \hdots:for{#1}\hfil}}
\def\hdots:for#1{\[email protected]\mkern-#1\dotsspace@
\xleaders\hbox{$\m@th\mkern#1\dotsspace@.\mkern#1\dotsspace@$}%
\hfill
\mkern-#1\dotsspace@}
\NewConfigure{hdotsfor}[1]{\def\a:hdotsfor##1{#1}}
\let\a:hdotsfor=\hdots:for
\def\:tempc{\a:hdotsfor}
\HLet\hdots:for\:tempc
\expandafter\ifx \csname tmp:muskip\endcsname\relax
\csname newmuskip\endcsname \tmp:muskip
\fi
\expandafter\def\csname tmspace \endcsname#1#2#3{%
\ifmmode
\bgroup
\tmp:muskip #1#2\edef\mathglue{\the\tmp:muskip}%
\tmp:dim #1#3\edef\textspace{\the\tmp:dim}\a:tmspace
\egroup
\else \kern #1#3\fi \relax
}
\edef\:tempc{\noexpand\protect
\expandafter\noexpand\csname tmspace \endcsname}
\HLet\tmspace=\:tempc
\NewConfigure{tmspace}{1}
\Configure{tmspace}{\mskip\mathglue}
\HRestore\over
\def\:tempc{\pic:gobble\a:over \o:@@over: \pic:gobble\b:over}
\HLet\@@over\:tempc
\HRestore\atop
\def\:tempc{\pic:gobble\a:atop \o:@@atop: \pic:gobble\b:atop}
\HLet\@@atop\:tempc
\def\::above{\pic:gobble\a:above \o:@@above:\tmp:dim
\pic:gobble\b:above }
\def\:above{\afterassignment\::above}
\def\:tempc{\Protect\:above \tmp:dim=}
\HLet\@@above\:tempc
\HRestore\abovewithdelims
\def\::abovewithdelims#1#2{\pic:gobble\a:abovewithdelims
\o:@@abovewithdelims:#1#2\tmp:dim\pic:gobble\b:abovewithdelims}
\def\:abovewithdelims#1#2{\def\:temp{\::abovewithdelims#1#2}%
\afterassignment\:temp\tmp:dim}
\def\:tempc{\Protect\:abovewithdelims }
\HLet\@@abovewithdelims\:tempc
\NewConfigure{abovewithdelims}{2}
\HRestore\overwithdelims
\def\:overwithdelims#1#2{\pic:gobble\a:overwithdelims
\o:@@overwithdelims:#1#2\pic:gobble\b:overwithdelims}
\def\:tempc{\Protect\:overwithdelims}
\HLet\@@overwithdelims\:tempc
\NewConfigure{overwithdelims}{2}
\HRestore\atopwithdelims
\def\:atopwithdelims#1#2{\pic:gobble\a:atopwithdelims
\o:@@atopwithdelims:#1#2\pic:gobble\b:atopwithdelims}
\def\:tempc{\Protect\:atopwithdelims}
\HLet\@@atopwithdelims\:tempc
\NewConfigure{atopwithdelims}{2}
\let\ltx@label\lb:l
\let\Mathaccent:\mathaccent@
\def\mathaccent@#1#2{\ifx \EndPicture\:UnDef
\DN@{\Picture+{}\Mathaccent:{#1}{#2}\EndPicture}%
\else\DN@{\Mathaccent:{#1}{#2}}\fi\next@}
\def\:temp#1{{\a:boxed\leavevmode
\vbox{\m@th$\displaystyle#1$}\b:boxed}}
\HLet\boxed\:temp
\NewConfigure{boxed}{2}
\newcommand\:temp:xrightarrow[2][]{\a:xrightarrow {\o:xrightarrow:[#1]{#2}}\b:xrightarrow}
\HLet\xrightarrow\:temp:xrightarrow
\NewConfigure{xrightarrow}{2}
\newcommand\:temp:xleftarrow[2][]{\a:xleftarrow {\o:xleftarrow:[#1]{#2}}\b:xleftarrow}
\HLet\xleftarrow\:temp:xleftarrow
\NewConfigure{xleftarrow}{2}
\def\:tempc#1{\a:eqref\o:eqref:{#1}\b:eqref}
\NewConfigure{eqref}{2}
\def\equation{\bgroup \@fleqnfalse
%
\ifx \EndPicture\:Undef
\def\endequation{%
\let\tagform@=\:gobble
\if@eqnsw \expand:after{%
%
\o:endequation:\b:equation\equ:no}%
\else \expand:after{%
\ifx\df@tag\@empty \expand:after{\o:endequation:\egroup}%
\else
\global\let\df:tag=\df@tag
\expand:after{\o:endequation: \expandafter\b:equation\ifdefined\ams:delete:tag\else\df:tag\fi%
\global\let\ams:delete:tag\@undefined
}\fi
}\fi
\c:equation\egroup
}%
\expandafter\a:equation
\else
\def\endequation{\o:endequation:\egroup}%
\fi
\o:equation:}
\expandafter\let\csname o:equation*:\expandafter
\endcsname \csname equation*\endcsname
\expandafter\let\csname o:endequation*:\expandafter
\endcsname \csname endequation*\endcsname
\expandafter\def\csname equation*\endcsname{\bgroup
\ifx \EndPicture\:Undef
\expandafter\def\csname endequation*\endcsname {%
\csname o:endequation*:\endcsname\egroup%
\csname b:equation*\endcsname\egroup
}%
\csname a:equation*\endcsname
\else
\expandafter\def\csname endequation*\endcsname{\csname
o:endequation*:\endcsname\egroup}%
\fi
\csname o:equation*:\endcsname}
\NewConfigure{equation*}[2]{
\expandafter\c:def \csname a:equation*\endcsname {#1\bgroup \let \@eqnnum \empty }%
\expandafter\c:def \csname b:equation*\endcsname {#2}%
}
\expandafter\def\csname genfrac \endcsname#1#2#3#4{%
\def\@tempa{#1#2}%
\edef\@tempb{\@nx\@genfrac\@mathstyle{#4}%
\expandafter\noexpand\csname @@\ifx @#3@over\else above\fi
\ifx\@tempa\@empty \else withdelims\fi\endcsname}%
\@tempb{#1#2#3}}
\def\:tempc#1#2#3#4#5{{\a:genfrac#1\b:genfrac{\c:genfrac#4#2#3\relax
{\d:genfrac#5\e:genfrac}}\f:genfrac}}
\HLet\@genfrac\:tempc
\NewConfigure{genfrac}{6}
\HRestore\frac
\def\:temp#1#2{{\a:frac\begingroup
#1\endgroup\b:frac \@@over \c:frac #2\d:frac}}
\expandafter\HLet\csname frac \endcsname\:temp
\def\math@cr@@[#1]{\ifnum0=`{\fi \iffalse}\fi\math@cr@@@
\o:noalign:{\vskip#1\relax}}
\catcode`\#13 \catcode`\!6
\def\reg:align!1!2{%
\ifx \ifinany@\:Undef\else \inany@true\fi
\inalign@true \ifx \displaybreak@\:UnDef
\chardef\dspbrk@context\z@
\else
\displaybreak@
\fi
\intertext@
\ifingather@\else\displ@y@\fi\Let@ \let\math@cr@@@\math@cr@@@align
\ifxxat@\else \let\tag\tag@in@align \fi
\let\label\label@in@display !1% set st@r
\ifst@rred\else \global\@eqnswtrue \fi \measure@{!2}%
\global\row@\z@ \tabskip\eqnshift@
\Configure{PauseMkHalign}
{\Configure{PauseMkHalign}{}{}{}{}\expandafter\clean:span}{}{}{}%
%
\SaveMkHalignConf:g{\align:type}\HRestore\noalign
\MkHalign#{\span
&\@lign$\m@th\displaystyle{{\HCode{}}%
#}$%
&\@lign$\m@th\displaystyle{{\HCode{}}%
#}$%
}!2%
}
\catcode`\#=6 \catcode`\!=12
\def\clean:span#1\c:halign{%
\TeXhalign \bgroup \:span}
\ifx \ifinany@\:Undef
\def\:tempc{%
\math@cr
\EndMkHalign \RecallMkHalignConfig \csname b:\align:type\endcsname
\ifingather@ \restorealignstate@ \egroup \nonumber
\ifnum0=`{\fi\iffalse}\fi%
\else $$\fi
\global\@ignoretrue
}
\else
\def\:tempc{%
\math@cr
\EndMkHalign \RecallMkHalignConfig \csname b:\align:type\endcsname
\ifingather@ \restorealignstate@ \egroup \nonumber
\ifnum0=`{\fi}%
\else $$\fi
\global\@ignoretrue
}
\fi
\HLet\endalign\:tempc
\def\:tempc{\pic:MkHalign{\align:type}}
\HLet\align@\:tempc
\def\Config:alg#1#2#3#4#5#6#7{%
\expandafter\c:def\csname a:#7\endcsname{\global
\let\sv:amps\add:amps #1}%
\expandafter\c:def\csname b:#7\endcsname{#2\global
\let\add:amps\sv:amps}%
\expandafter\c:def\csname c:#7\endcsname{#3}%
\expandafter\c:def\csname d:#7\endcsname{#4}%
\expandafter\c:def\csname e:#7\endcsname{\expandafter\align:td
\expandafter{\csname f:#7\endcsname}{#5}{#6}}%
}
\def\align:td#1#2#3{\iftag@
\ifnum \add:amps>0
\gHAdvance\add:amps -1 \gHAdvance\HCol -1
\global\let#1\empty
\ifnum \add:amps=0 \gHAdvance\HCol1 #2\gdef#1{#3}\fi
\else #2\gdef#1{#3}\fi
\else \gHAssign\add:amps\HCol\relax #2\gdef#1{#3}\fi}%
\def\:tempc#1{%
\expandafter\pend:def\csname #1\endcsname{\def\align:type{#1}}%
\NewConfigure{#1}[6]{\Config:alg{##1}{##2}{##3}{##4}{##5}{##6}{#1}}%
\Configure{#1}{}{}{}{}{}{}%
\def\:temp{#1}\def\:tempa{align}\ifx \:temp\:tempa\else
\@xp\let\csname reg:#1\endcsname\reg:align
\@xp\let\csname end#1\endcsname\endalign
\fi }
\:tempc{alignat}
\:tempc{alignat*}
\:tempc{xalignat}
\:tempc{xalignat*}
\:tempc{xxalignat}
\:tempc{align}
\:tempc{align*}
\:tempc{flalign}
\:tempc{flalign*}
\pend:defIII\start@align{\Configure{$$}{}{}{}}
\catcode`\#13 \catcode`\!6
\def\reg:start@aligned!1!2{%
\savecolumn@
\vcenter \bgroup
\maxfields@!2\relax
\ifnum\maxfields@>\m@ne
\multiply\maxfields@\tw@
\let\math@cr@@@\math@cr@@@alignedat
\else
\let\math@cr@@@\math@cr@@@aligned
\fi
\Let@ \chardef\dspbrk@context\@ne
\default@tag
\global\column@\z@
\SaveMkHalignConf:g{start@aligned}\HRestore\noalign
\MkHalign#{&\column@plus $\m@th\displaystyle{{\HCode{}}#}$%
&\column@plus $\m@th\displaystyle{{\HCode{}}#}$}%
}
\catcode`\#=6 \catcode`\!=12
\def\al:gned#1{%
\Configure{start@aligned}{\csname a:#1\endcsname}%
{\csname b:#1\endcsname}{\csname c:#1\endcsname}%
{\csname d:#1\endcsname}{\csname e:#1\endcsname}%
{\csname f:#1\endcsname}\pic:MkHalign{#1}}
\NewConfigure{start@aligned}{6}
\def\:tempc{\crcr\EndMkHalign
\RecallMkHalignConfig \restorecolumn@
\egroup \b:start@aligned}
\HLet\endaligned\:tempc
\def\:temp{%
\let\@testopt\alignsafe@testopt
\futurelet\:temp\aligned:a}
\def\aligned:a{\ifx [\:temp \expandafter\aligned:b
\else \def\:temp{\aligned:b[c]}\expandafter\:temp \fi}
\def\aligned:b[#1]{%
\al:gned{aligned}{#1}\m@ne}
\HLet\aligned\:temp
\def\reg:aligned{\reg:start@aligned}
\NewConfigure{aligned}{6}
\def\:temp{\futurelet\:temp\alignedat:a}
\def\alignedat:a{\ifx [\:temp \expandafter\alignedat:b
\else \def\:temp{\alignedat:b[c]}\expandafter\:temp \fi}
\def\alignedat:b[#1]{%
\let\@testopt\alignsafe@testopt
\al:gned{alignedat}{#1}\m@ne}
\HLet\alignedat\:temp
\def\reg:alignedat{\reg:start@aligned}
\NewConfigure{alignedat}{6}
\catcode`\#13 \catcode`\!6
\def\reg:gathered[!1]{%
\RIfM@\else
\nonmatherr@{\begin{gathered}}%
\fi
\null \vcenter\bgroup
\Let@ \chardef\dspbrk@context\@ne \restore@math@cr
\SaveMkHalignConf:g{gathered}%
\MkHalign#{$\m@th\displaystyle{\HCode{}}#$}%
}
\catcode`\#=6 \catcode`\!=12
\def\:tempc{\crcr\EndMkHalign
\RecallMkHalignConfig \egroup\b:gathered}
\HLet\endgathered\:tempc
\def\:temp{\pic:MkHalign{gathered}}
\expandafter\HLet\csname \string\gathered\endcsname\:temp
\NewConfigure{gathered}{6}
\catcode`\#13 \catcode`\!6
\def\reg:multline!1{%
\ifx \ifinany@\:Undef\else \inany@true\fi
\Let@
\@display@init{\global\advance\row@\@ne \global\dspbrk@lvl\m@ne}%
\ifx \displaybreak@\:UnDef
\chardef\dspbrk@context\z@
\else
\displaybreak@
\fi
\restore@math@cr \let\tag\tag@in@align
\global\tag@false \global\let\raise@tag\@empty
\let\tag\gobble@tag \ifst@rred \let\label\@gobble \else
\stepcounter{equation}%
\def\label{\let\cnt:currentlabel\@currentlabel
\def\:@currentlabel{\ifx \cnt:currentlabel\@currentlabel
\the\c@equation\else \@currentlabel\fi}%
\anc:lbl r{equation}\ltx@label}%
\edef\@currentlabel{\the\c@equation}%
\fi
%
\ifst@rred
\expandafter\let\csname e:multline*\endcsname\empty
\expandafter\let\csname f:multline*\endcsname\empty
\fi
\SaveMkHalignConf:g{multline\ifst@rred *\fi}\HRestore\noalign
\MkHalign#{\hbox{$\m@th\displaystyle{\HCode{}}%
#$}}!1%
}
\catcode`\#=6 \catcode`\!=12
\def\:tempc{\ifst@rred\else
\e:multline\csname a:multline-num\endcsname
\tagform@\theequation\csname b:multline-num\endcsname\f:multline
\fi
\math@cr \EndMkHalign
\RecallMkHalignConfig \csname b:multline\ifst@rred *\fi\endcsname
$$\global\@ignoretrue }
\HLet\endmultline\:tempc
\def\:tempc{\pic:MkHalign{multline\ifst@rred *\fi}}
\HLet\multline@\:tempc
\NewConfigure{multline}{6}
\NewConfigure{multline-num}{2}
\@xp\let\csname reg:multline*\endcsname\reg:multline
\@xp\let\csname endmultline*\endcsname\endmultline
\NewConfigure{multline*}{4}
\catcode`\#13 \catcode`\!6
\def\reg:gather!1{%
\ingather@true \ifx \ifinany@\:Undef
\let\split\insplit@ \chardef\dspbrk@context\z@
\else
\inany@true
\fi
%
\let\tag\tag@in@align \let\label\label@in@display
\intertext@ \displ@y@
\Let@ \let\math@cr@@@\math@cr@@@gather
\global\shifttag@false \global\row@\@ne
\SaveMkHalignConf:g{gather\ifst@rred *\fi}\HRestore\noalign
\MkHalign#{\hbox{$\m@th\displaystyle{{\HCode{}}%
#}$}%
&\hbox{{\HCode{}}%
#}%
}!1%
}
\catcode`\#=6 \catcode`\!=12
\def\:tempc{\math@cr \EndMkHalign
\RecallMkHalignConfig \csname b:gather\ifst@rred *\fi\endcsname
$$\global\@ignoretrue }
\HLet\endgather\:tempc
\def\:tempc{\pic:MkHalign{gather\ifst@rred *\fi}}
\HLet\gather@\:tempc
\NewConfigure{gather}{6}
\@xp\let\csname reg:gather*\endcsname\reg:gather
\@xp\let\csname endgather*\endcsname\endgather
\NewConfigure{gather*}{6}
\def\:tempc{%
\def\intertext##1{%
\ifvmode\else\\\@empty\fi
\noalign{%
\penalty\postdisplaypenalty\vskip\belowdisplayskip
\vbox{\normalbaselines
\ifdim\linewidth=\columnwidth
\else \parshape\@ne \@totalleftmargin \linewidth
\fi
\a:intertext \noindent##1\b:intertext\par}%
\penalty\predisplaypenalty\vskip\abovedisplayskip%
}%
}}
\HLet\intertext@=\:tempc
\NewConfigure{intertext}{2}
\HLet\leftroot\:gobble
\HLet\uproot\:gobble
\catcode`\#13 \catcode`\!6
\def\reg:smallmatrix{%
\vcenter\bgroup \Let@\restore@math@cr\default@tag
\SaveMkHalignConf:g{smallmatrix}%
\MkHalign#{$\m@th\scriptstyle#$&&%
$\m@th\scriptstyle#$}%
}
\catcode`\#=6 \catcode`\!=12
\def\:tempc{\crcr\EndMkHalign
\RecallMkHalignConfig \egroup\b:smallmatrix}
\HLet\endsmallmatrix\:tempc
\def\:temp{\pic:MkHalign{smallmatrix}}
\HLet\smallmatrix\:temp
\NewConfigure{smallmatrix}{6}
\pend:defI\substack{\a:substack}
\append:defI\substack{\b:substack}
\NewConfigure{substack}{2}
\catcode`\#13 \catcode`\!6
\def\reg:subarray!1{%
\vcenter\bgroup
\Let@ \restore@math@cr \default@tag
\baselineskip\fontdimen10 \scriptfont\tw@
\advance\baselineskip\fontdimen12 \scriptfont\tw@
\lineskip\thr@@\fontdimen8 \scriptfont\thr@@
\let\e:subarray\empty \let\f:subarray\empty
\everycr{}\SaveMkHalignConf:g{subarray}%
\MkHalign#{$\m@th\scriptstyle#$}%
}
\catcode`\#=6 \catcode`\!=12
\def\:tempc{\crcr\EndMkHalign
\RecallMkHalignConfig \egroup\b:subarray}
\HLet\endsubarray\:tempc
\def\:temp#1{\def\Hlcr{#1}\pic:MkHalign{subarray}{#1}}
\HLet\subarray\:temp
\NewConfigure{subarray}{4}
\NewConfigure{split}{6}
\catcode`\#13 \catcode`\!6
\def\:tempc{%
\vbox\bgroup
\ifx \ifinany@\:Undef
\chardef\dspbrk@context\@ne
\fi
%
\Let@ \restore@math@cr \default@tag \everycr{}\a:split
\SaveMkHalignConf:g{split}\HRestore\noalign
\MkHalign#{ $\m@th\displaystyle{{\HCode{}}%
#}$%
&$\m@th\displaystyle{{\HCode{}}%
#}$%
}}
\HLet\insplit@\:tempc
\catcode`\#6 \catcode`\!12
\def\:tempc{%
\crcr\EndMkHalign \b:split \egroup }
\HLet\endsplit\:tempc
\Configure{@begin}
{split}
{\relax
\ifx \split\insplit@ \else
\def\choose:begin{\global\let\choose:begin\@firstoftwo
\@secondoftwo}%
\fi
}
\NewConfigure{equations}[2]{\def\pic:equa{#1}\def\pic:equb{#2}}
\def\str:pic{\ifx \EndPicture\:UnDef
\expandafter\Picture\pic:equa{ \pic:equb}%
\else \let\EndPicture\empty \fi
\let\halign\TeXhalign}
\def\make@df@tag@@#1{%
\gdef\df@tag{\maketag@@@{#1}\def\@currentlabel{#1}\gdef\ams:delete:tag{}%
\let\cnt:currentlabel\@currentlabel
\def\:@currentlabel{\ifx \cnt:currentlabel\@currentlabel
\expandafter\the\csname c@equation\endcsname\else \@currentlabel\fi}%
%
\anc:lbl r{}%
}}
\def\make@df@tag@@@#1{\gdef\df@tag{\tagform@{#1}%
\toks@\@xp{\p@equation{#1}}\edef\@currentlabel{\the\toks@}%
\let\cnt:currentlabel\@currentlabel
\def\:@currentlabel{\ifx \cnt:currentlabel\@currentlabel
\expandafter\the\csname c@equation\endcsname\else \@currentlabel\fi}%
%
\anc:lbl r{}%
}}
\:CheckOption{new-accents} \if:Option \else
\HLet\Hat\hat
\HLet\Check\check
\HLet\Tilde\tilde
\HLet\Acute\acute
\HLet\Grave\grave
\HLet\Dot\dot
\HLet\Ddot\ddot
\HLet\Breve\breve
\HLet\Bar\bar
\HLet\Vec\vec
\fi
\expandafter\def\csname [ \endcsname{\st:Math}
\expandafter\def\csname ] \endcsname{\ed:Math}
\let\:tempc\measure@
\pend:defI\:tempc{\bgroup
\RecallTeXcr \HRestore\noalign \let\EndPicture\empty
\let\halign\TeXhalign \let\span\:span \HRestore\begin
\HRestore\end \a:measure@ }
\append:defI\:tempc{\egroup}
\HLet\measure@\:tempc
\NewConfigure{measure@}{1}
\HLet\savealignstate@\empty
\renewcommand{\n:smash:}[2][tb]{%
\def\smash@{#1}%
\ifmmode\@xp\o:mathpalette:\@xp\mathsm@sh\else
\@xp\makesm@sh\fi{#2}}
\let\:tempc\maketag@@@
\pend:defI\:tempc{\a:maketag}
\append:defI\:tempc{\b:maketag}
\NewConfigure{maketag}{2}
\HLet\maketag@@@\:tempc
\MathSymbol\mathrel{@cdots}
\MathSymbol\mathop{doteq}
\def\n:doteq:{\expandafter\:same \math:sym\mathop{doteq}\nolimits}
\HLet\dotsb@=\@cdots
\HLet\intdots@=\@cdots
\HRestore\cdots
\MathSymbol\mathop{iint}
\def\n:iint:{\expandafter\:same \math:sym\mathop{iint}\nolimits}
\MathSymbol\mathop{iiint}
\def\n:iiint:{\expandafter\:same \math:sym\mathop{iiint}\nolimits}
\MathSymbol\mathop{iiiint}
\def\n:iiiint:{\expandafter\:same \math:sym\mathop{iiiint}\nolimits}
\MathSymbol\mathop{idotsint}
\def\n:idotsint:{\expandafter\:same \math:sym\mathop{idotsint}\nolimits}
\def\:tempc#1{\a:underrightarrow
\o:underrightarrow:{#1}\b:underrightarrow}
\HLet\underrightarrow\:tempc
\NewConfigure{underrightarrow}{2}
\def\:tempc#1{\a:underleftarrow
\o:underleftarrow:{#1}\b:underleftarrow}
\HLet\underleftarrow\:tempc
\NewConfigure{underleftarrow}{2}
\def\:tempc#1{\a:overleftrightarrow
\o:overleftrightarrow:{#1}\b:overleftrightarrow}
\HLet\overleftrightarrow\:tempc
\NewConfigure{overleftrightarrow}{2}
\def\:tempc#1{\a:underleftrightarrow
\o:underleftrightarrow:{#1}\b:underleftrightarrow}
\HLet\underleftrightarrow\:tempc
\NewConfigure{underleftrightarrow}{2}
\def\:tempc#1#2#3{\a:underarrow@
\hbox{$\m@th#2#3$}\b:underarrow@
\hbox{#1#2}\c:underarrow@
}
\HLet\underarrow@\:tempc
\def\:tempc#1#2#3{\a:overarrow@
\hbox{#1#2}\b:overarrow@
\hbox{$\m@th#2#3$}\c:overarrow@
}
\HLet\overarrow@\:tempc
\NewConfigure{underarrow@}{3}
\NewConfigure{overarrow@}{3}
\def\:temp#1#2{\a:overset\binrel@{#2}%
\binrel@@{\mathop{\kern\z@#2}\limits^{#1}}\b:overset}
\HLet\overset\:temp
\NewConfigure{overset}{2}
\def\:temp#1#2{\a:underset\binrel@{#2}%
\binrel@@{\mathop{\kern\z@#2}\limits_{#1}}\b:underset}
\HLet\underset\:temp
\NewConfigure{underset}{2}
\MathSymbol\mathop{dotsc}
\MathSymbol\mathop{dotso}
\MathSymbol\mathrel{longleftarrow}
\MathSymbol\mathrel{longrightarrow}
\ifx \ifinany@\:Undef
\let\:tempc\gather@split
\append:defIII\:tempc{%
\def\endmathdisplay@a{%
\math@cr \EndMkHalign
\RecallMkHalignConfig \csname b:gather\ifst@rred *\fi\endcsname
\egroup
}%
}
\HLet\gather@split\:tempc
\else
\:warning{ams files too old for TeX4ht}
\fi
\Hinput{amsmath}
\endinput
结果如下：
