# How to typset $:\iff$ (logical equivalence)? [duplicate]

How shall I typeset ":<=>" in Latex which means "is logical equivalent"? After typing A :\iff B I get

Comparing it with A \coloneqq B (cf. How to typeset $:=$ correctly? ):

We see that there is a bigger space between the colon and the \iff symbol in A :\iff B. Unfortunately I haven't found a symbol in mathtools for this purpose...

My attempts: The result of A \ordinarycolon\iff B

and A \vcentcolon\iff B:

• @LaRiFaRi: Perfect ;-) This can question can be thus marked as a duplicate... – Stephan Kulla Nov 18 '15 at 15:08
• glad to hear that. If you want to have a long version it would be % arara: pdflatex \documentclass{article} \usepackage{mathtools} \begin{document} $A \vcentcolon\Longleftrightarrow B$ \end{document} – LaRiFaRi Nov 18 '15 at 15:12