The use of “tilde” changes the proximity to the set theory symbol (ref img)

Question

I just want to format a simple set theory example. But the following is annoying:

See how close the cap gets to the 'A' because of the tilde sign? I've used sim for the tilde sign. Any suggestions?

Answer 1

You could avoid the binary operator spacing by writing {\sim} or \mathord{\sim}, achieving the same. You might have another look at Spacing around a character in math mode.

Answer 2

You could use one of the following commands:

\, (\thinspace) 
\: (\medspace)
\; (\thickspace)
\quad 
\qquad

(They generate different spaces, but I don't know how to mark them in the code.) See also the short math guide, p. 11.

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EDIT: This solution should't be used here (see comments below). However, I'll not delete it as there is no harm to know about these commands.

Answer 3

I believe it's doing that because \sim is meant as a binary operator (between two elements), rather than as a unary prefix operator (like set complement or negation).

You can always manually fix it up with extra space \; or negative space \! so for example, this looks approximately right:

A\; \cap \sim\!\!B

Answer 4

Here is a complete code example with output (I just took Stefan's answer and wrote it out).

\documentclass{standalone}
% TEX.SE \url{}
\setlength{\textwidth}{4in}
\begin{document}
\Huge
$A = (A \cup B)$

$A \cap (( A) \cap B) = A \cap \mathord{\sim}B$
\end{document}

Switching in and out of math mode is not a good way to get extra spaces. If you still want them after classifying the tilde as an ordinal, you can insert them with \,, \;, or \. See Herbert's mathmode document for FMTYEWTK.