% Adapted from ltmath.dtx.

% This should be loaded after "amsmath" to nuke its stupid definitions.

% The \noindent enters unrestricted horizontal mode without putting a
% (possibly empty) hbox for paragraph indentation at the beginning of
% the first line of the paragraph.
% Otherwise, if $$ is invoked in vertical mode, it is implicitly
% preceded by \indent which enters horizontal mode but adds the
% indentation hbox.
% The paragraph indentation hbox's width will have 2em added to it to
% determine \predisplaysize, which for very wide displayed equations
% can cause \abovedisplayskip and \belowdisplayskip to be used instead
% of \abovedisplayshortskip and \belowdisplayshortskip.

\makeatother
  \def\[{%
    \relax
    \ifmmode
      \@badmath
    \else
      \ifvmode
        % Replaced these two lines:
        %\nointerlineskip
        %\makebox[.6\linewidth]%
        % by this line:
        \noindent
      \fi
      $$%%$$ BRACE MATCH HACK
    \fi
  }
  \def\]{%
    \relax
    \ifmmode
      \ifinner
        \@badmath
      \else
        $$%%$$ BRACE MATCH HACK
      \fi
    \else
      \@badmath
    \fi
    \ignorespaces
  }
\makeatletter