%AM: This should go to supp-box.tex. 

%D \macros
%D   {llap, rlap, tlap, blap, clap}
%D
%D Some well known friends, but we implement them our own
%D way. We want the macros to work in both math and text mode.

\def\dorlap{\begingroup\dowithnextbox{\normalhbox to \zeropoint
   {\flushnextbox\normalhss}\endgroup}\normalhbox}

\def\dollap{\begingroup\dowithnextbox{\normalhbox to \zeropoint
   {\normalhss\flushnextbox}\endgroup}\normalhbox}

\def\doclap{\begingroup\dowithnextbox{\normalhbox to \zeropoint
   {\normalhss\flushnextbox\normalhss}\endgroup}\normalhbox}

\def\domathclap{\mathpalette\dodomathclap}
\def\dodomathclap#1#2{\doclap{$\m@th#1#2$}}

\def\domathllap{\mathpalette\dodomathllap}
\def\dodomathllap#1#2{\dollap{$\m@th#1#2$}}

\def\domathrlap{\mathpalette\dodomathrlap}
\def\dodomathrlap#1#2{\dorlap{$\m@th#1#2$}}

\unexpanded\def\rlap{\mathortext\domathrlap\dorlap}
\unexpanded\def\llap{\mathortext\domathllap\dollap}
\unexpanded\def\clap{\mathortext\domathclap\doclap}

%AM: I do not know where this belongs. Perhaps supp-mat.tex

%D \macros {cramed}
%D
%D \TEX provides no primitive to force in cramped math mode.
%D Here is a macro that does so. It is based on a solution by
%D Don Knuth
%D \userul{http://www.ctan.org/tex-archive/digests/tex-implementors/042}.
%D The explanation is by Morten Høgholm's mathtools package.

\def\cramped
  {\mathpalette\docramped}

\def\docramped#1#2%
%D Force a cramped style by issuing a non||existing radical
  {\setbox\scratchbox=\hbox{\nulldelimiterspace=\zeropoint%
                            $\m@th#1\radical\zerocount{#2}$}
%D Make sure the height is correct
   \ifx#1\displaystyle
      \scratchdimen=\fontdimen8\textfont3
      \advance\scratchdimen .25\fontdimen5\textfont2
   \else
      \scratchdimen=1.25\fontdimen8
      \ifx#1\textstyle\textfont
      \else
        \ifx#1\scriptstyle\scriptfont\else\scriptscriptfont\fi
      \fi      
      3
    \fi
    \advance\scratchdimen-\ht\scratchbox
    \ht\scratchbox=-\scratchdimen
    \box\scratchbox}

%AM: Not sure about these either. Either supp-box or supp-mat
%AM: core-mat.

%D \macros 
%D    {cramedllap, crampedrlap, crampedclap}
%D In many cases, one wants to use the \tex{clap} macro in
%D math mode while using subscripts. Normally, subscripts are
%D in cramped mode, and these macros allow you to go to
%D cramped mode. For example
%D \startbuffer
%D \startformula
%D   \sum_{a^2 < b^2 < c^2} \quad
%D   \sum_{\clap{a^2 < b^2 < c^2}} \quad
%D   \sum_{\crampedclap{a^2 < b^2 < c^2}}
%D \stopformula
%D \stopbuffer
%D \typebuffer{\switchtobodyfont[24pt]\getbuffer}
%D Notice that \type{\clap{\cramped ... }} would also work,
%D but it requires \TEX\ to typeset it arguments 16 times.

\def\docrampedllap#1#2{{}\dollap{\docramped #1{#2}}}
\def\docrampedrlap#1#2{{}\dorlap{\docramped #1{#2}}}
\def\docrampedclap#1#2{{}\doclap{\docramped #1{#2}}}

\def\crampedllap{\mathpalette\docrampedllap}
\def\crampedrlap{\mathpalette\docrampedrlap}
\def\crampedclap{\mathpalette\docrampedclap}

%AM: This needs to replace the core-mat macros.

%D \macros
%D   {substack}
%D
%D Preliminary code:
%D
%D \startbuffer
%D \startformula
%D    \sum_{%
%D      \startsubstack
%D       i = 1 \NR
%D       i \neq n \NR
%D       i \neq m
%D       \stopsubstack
%D     }a_i
%D \stopformula
%D \stopbuffer
%D \getbuffer which was typed as \typebuffer
%D Notice that these macros give the correct spacing for
%D subscripts. Compare for example
%D \startbuffer
%D \startformula
%D \sum_{\startsubstack a \NR b \NR \stopsubstack} 
%D \text{ and }
%D \sum_{\scriptstyle a \atop \scriptstyle}
%D \stopformula
%D \typebuffer which gives \getbuffer

\def\startsubstack
  {%\bgroup% Is this ok?
   \vcenter\bgroup
    \baselineskip\fontdimen10 \scriptfont\plustwo
    \advance\baselineskip\fontdimen12 \scriptfont\plustwo
    \lineskip\plusthree\fontdimen8 \scriptfont\plusthree
    \lineskiplimit\lineskip
    \let\stopmathmode\relax
    \def\NC{\domatrixNC}%
    \def\MC{\domatrixNC\startmathmode}%
    \global\let\domatrixNC\dodomatrixNC
    \def\NR
      {\stopmathmode
       \global\let\domatrixNC\dodomatrixNC
       \crcr}%
    \mathsurround\zeropoint
    \everycr\emptytoks
    \halign\bgroup\hfil$\scriptstyle##$\hfil\crcr}

\def\stopsubstack
  {\crcr
   \egroup
   \egroup
   %\egroup% Is this ok?
   }

%AM: These need to go into math-tex. Perhaps I should also
%AM: port dotsint?

\def\dointkern  {\mkern-6mu\mathchoice{\mkern-3mu}{}{}{}}

\definemathcommand  [iint]     {\repeatintegral{1}}
\definemathcommand  [iiint]    {\repeatintegral{2}}
\definemathcommand  [iiiint]   {\repeatintegral{3}}

\def\repeatintegral#1%
  {\scratchtoks\emptytoks
   \let\dointlimits\nolimits
   \dorecurse{#1}{\appendtoks \intop \dointkern \to \scratchtoks}
   \appendtoks \intop \dointlimits \to \scratchtoks
   \edef\dodorepeatintegral{\the\scratchtoks}
   \futurelet\next\dorepeatintegral}

%D If the \type{\limits} option is used after \type{\iint}, use
%D \type{\mathop} and fudge the left hand space a bit to make the
%D subscript visually centered.

\def\dorepeatintegral
   {\ifx\limits\next               \dointlimitcorrection
    \else \ifx \displaylimits\next \dointlimitcorrection
    \fi\fi
    \dodorepeatintegral}

\def\dointlimitcorrection
  {\mkern-7mu\mathchoice{\mkern-2mu}{}{}{}%
   \mathop\bgroup
      \mkern7mu\mathchoice{\mkern2mu}{}{}{}%
      \let\dointlimits\egroup}


%AM: This needs to go to m-newmat.tex

%D \macros {splitfrac, splitdfrac}
%D Occasionally one needs to typeset multi||line fractions.
%D These commands use \tex{genfrac} to create such fractions.
%D \startbuffer
%D \startformula
%D      a=\frac{
%D          \splitfrac{xy + xy + xy + xy + xy}
%D                    {+ xy + xy + xy + xy}
%D        }
%D        {z}
%D      =\frac{
%D          \splitdfrac{xy + xy + xy + xy + xy}
%D                    {+ xy + xy + xy + xy}
%D        }
%D        {z}
%D \stopformula
%D \stopbuffer
%D \typebuffer \getbuffer
%D
%D These macros are based on Michael J.~Downes posting on
%D comp.text.tex on 2001/12/06

\def\splitfrac#1#2%
  {\genfrac{}{}{0pt}{1}%
    {\textstyle#1\quad\hfill}%
    {\textstyle\hfill\quad\mathstrut#2}}

\def\splitdfrac#1#2%
  {\genfrac{}{}{0pt}{0}%
    {#1\quad\hfill}
    {\hfill\quad\mathstrut #2}}