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

Barbara Beeton bnb at ams.org
Mon May 25 21:08:30 CEST 2009

On Mon, 25 May 2009, Uwe Lueck wrote:

    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.

correct.  thanks, uwe.

in the case of \le and \leq, both are
defined in plain.tex; the basic one is
\leq, and then  \let\le=\leq .
so this was don knuth's decision.
							-- bb

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