I want to have an equal by definition symbol of an equal sign with the
roman letters "def" above it.  I currently use the macro

\newcommand{\ebd}{\ensuremath{\stackrel{{\text{\tiny def}}}{=}}}

but the "def" is slightly too big -- it extends over the equal sign so
when aligning \ebd and "=" symbols in a multiline formula things don't
align up exactly.  Is there an easy way to get something slightly
smaller than the tiny version?  Thanks, ds

On Thu, 12 Aug 2010 08:15:11 -0700 (PDT), Dave94705
<david.jobman.schwartz@gmail.com> wrote:

>I want to have an equal by definition symbol of an equal sign with the
>roman letters "def" above it.  I currently use the macro
>
>\newcommand{\ebd}{\ensuremath{\stackrel{{\text{\tiny def}}}{=}}}
>
>but the "def" is slightly too big -- it extends over the equal sign so
>when aligning \ebd and "=" symbols in a multiline formula things don't
>align up exactly.  Is there an easy way to get something slightly
>smaller than the tiny version?  Thanks, ds

Making it small enough to not extend past the edges of the 
"=" sign would make it much too small and ugly. Even \tiny 
is too small. As I see it, you have three choices:

 1. Use a special symbol for "equal by definition". Some 
    symbols I've seen used for this include \doteq, \equiv, 
    \hateq (from, e.g., the MnSymbols package), and := or 
    the nicer looking \mathrel{\mathop:}=. The colon-equal 
    is typically wider than = and also ruins alignments.
 
2. Use a different alignment environment that aligns equal
    signs at their centers rather than on the left. You can 
    get this with array with a little work:
    \[\setlength{\arraycolsep}{0pt}
    \begin{array}{rcl}
      A&{}\ebd{}&2\\
      C&{}={}&A
    \end{array}\]

 3. Don't put \ebd in an alignment with other relations  
    Usually one can arrange for this, possibly even
    resulting in improved exposition.


Dan
To reply by email, change LookInSig to luecking