[texhax] Extra space above multline (Bug in amsmath?)

[Plamen Tanovski]

Hi,

I have noticed that the space above multline from amsmath.sty is
always bigger then the other environments. Carefully looking at the
examples in testmath.pdf or TLC2 also shows this difference. The space
above is gettig bigger if the text has to stretch vertically. There is
also even a bigger difference between equation and the other amsmath
environments! So, the different spacing, using equation and multline
on the same page, can be visually recognised. 

The \jot has to do with this extra space of multline. If I set \jot to
0 in the following example, the extra space of multline vanish. Is
this a bug? I can't imagine, that I am the first who finds this
difference. I've searched the newsgroups and the bug database but
didn't find something. Here is the example example.

\listfiles
\documentclass[12pt]{article}
\usepackage{amsmath,color}
\setlength{\multlinegap}{0.44\columnwidth}
%\setlength{\jot}{0pt}
\raggedbottom
\begin{document}

\begin{picture}(0,0)
  \makebox(0,0){%
    \begin{minipage}[t]{1.0\linewidth}
     \begin{multline*}
       XXX   
   \end{multline*}
 \end{minipage}}
\color{red}
\makebox(0,0){%
  \begin{minipage}[t]{1.0\linewidth}
      \begin{gather*}
    \begin{split}
    XXX
    \end{split}
  \end{gather*}
\end{minipage}}
\color{blue}
\makebox(0,0){%
  \begin{minipage}[t]{1.0\linewidth}
      \begin{equation*}
XXX
  \end{equation*}
\end{minipage}}
\color{yellow}
\makebox(0,0){%
  \begin{minipage}[t]{1.0\linewidth}
    \begin{align*}
    XXX
    \end{align*}
\end{minipage}}
\color{green}
\makebox(0,0){%
  \begin{minipage}[t]{1.0\linewidth}
    \begin{gather*}
    XXX
    \end{gather*}
\end{minipage}}
\end{picture}
\end{document}


 *File List*
      ml.tex
 article.cls    2004/02/16 v1.4f Standard LaTeX document class
  size12.clo    2004/02/16 v1.4f Standard LaTeX file (size option)
 amsmath.sty    2000/07/18 v2.13 AMS math features
 amstext.sty    2000/06/29 v2.01
  amsgen.sty    1999/11/30 v2.0
  amsbsy.sty    1999/11/29 v1.2d
  amsopn.sty    1999/12/14 v2.01 operator names
   color.sty    1999/02/16 v1.0i Standard LaTeX Color (DPC)
   color.cfg    2005/02/03 v1.3 color configuration of teTeX/TeXLive
   dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
dvipsnam.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
 ***********

Best regards,

-- 
Plamen Tanovski
Prager Str. 125
04317 Leipzig
Tel. (03 41) 3 08 57 60