# How to prevent a math symbol to change its type [relation, operator etc.] and modify the space around?

Typically, we take \leq:

\documentclass{article}

\begin{document}
$\leq \simeq \leq_A \sim \leq_B$

$\leq \simeq {\leq_A} \sim {\leq_B}$

\end{document}

and see the space around the two \sim is not respected as soon as we put a subletter on them Why does tex do that ? How to prevent it without having to put the braces around each new symbol or use a command to define leq taking an input?

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What would be the use of this? I think this will be prejudicial and would destroy one of the main typographical features of TeX; imagine what would happen (a simple example) to math typesetting if the minus sign were treated in the same fashion in both occurrences of $4-5\quad \times-3$. –  Gonzalo Medina Sep 12 '13 at 3:40
@GonzaloMedina I completely agree with your point, but the results are the opposite of what I'd naively think. Is LaTeX getting rid of the padding around concatenated relation symbols? In other words, if you mask the relation symbol, \leq, inside curly brackets, then does LaTeX treat the \sim as being between two non-relation symbols and thus restore the padding? –  A.Ellett Sep 12 '13 at 4:42
You have two choices: either adding braces around the symbol when it's used as an ordinary, or define a new command for it, say \newcommand{\oleq}{\mathord{\leq}}. –  egreg Sep 12 '13 at 6:39

Both $\leq \simeq \leq \sim \leq$ and $\leq \simeq \leq_A \sim \leq_B$ lead to similar results when it comes to spacing as all of the symbols are treated as relations.