[Tex/LaTex] wider equal sign

Question

I have defined the equal by definition sign:

with this code: \newcommand{\eqdef}{\overset{def}{=}}.

However, "def" extends over the edges of the equal sign. Is there a wider equal sign to use?

Answer 1

Just put two equals signs, backing up slightly:

\newcommand{\eqdef}{\overset{\mathrm{def}}{=\joinrel=}}

This is how TeX builds extensible arrows.

The magic macro \joinrel is defined as

\mathrel{\mkern-3mu}

and the magic is done by the fact that TeX doesn't put spaces between consecutive relation symbols:

=\mathrel{\mkern-3mu}=

will thus result in two equals signs slightly superimposed to each other.