[texhax] le vs leq and \ZZ vs \Z

[Uwe Lueck]

Barbara Beeton <bnb at ams.org> schrieb am 25.05.2009 20:39:00:
>     1. I'm using LaTeX for quite some time now and have always wondered why
>     there are two possibilities to typeset the "less or equal than" symbol.
> 
>     Why are there two commands "le" and "leq" to typeset the same symbol?
>     Is it just for historical reasons or is there a "proper" way to do it?
> 
> the choice of which to use is usually
> what is known as "house style"; in
> most situations, the single or double
> horizontal rule doesn't change the
> meaning, but some publishers prefer
> the single, and some the double rule.
> (some mathematicians also have strong
> preferences.)  so you could say it's
> historical.

No, Barbara, \le and \leq are synonyms for the same symbol, see TeXbook p. 436/438, there: 
"Some symbols have alternate names that are so commonly used that plain TeX provides two or more equivalent control sequences."

\leqq from the amssymb package has a double horizontal rule.

Cheers, 

    Uwe.