\hookrightarrow

[Jose Capco]

Dear NG,

When typing embeddings or injection maps I use \hookrightarrow in math-
mode. But this is sometimes too short for me. Is there a way to
elongate a symbol in LaTeX? I don't feel like using an extra package
just because I want a longer \hookrightarrow, so if this is not
possible without the use of an extra package I'll just put up with
\hookrightarrow

Sincerely,
Jose Capco

[Scott Pakin]

Post by Jose Capco
When typing embeddings or injection maps I use \hookrightarrow in math-
mode. But this is sometimes too short for me. Is there a way to
elongate a symbol in LaTeX? I don't feel like using an extra package
just because I want a longer \hookrightarrow, so if this is not
possible without the use of an extra package I'll just put up with
\hookrightarrow

LaTeX defines \hookrightarrow as \lhook\joinrel\rightarrow -- the
combination of a hook and a right arrow. It further defines \longrightarrow
as \relbar\joinrel\rightarrow -- the combination of a line and a right
arrow. All you need to do is combine the three parts (hook, line, arrow)
to produce a long, hooked right arrow:

\newcommand*{\longhookrightarrow}{\ensuremath{\lhook\joinrel\relbar\joinrel\rightarrow}}

-- Scott

[Adrian Nievergelt]

Post by Scott Pakin

Post by Jose Capco
When typing embeddings or injection maps I use \hookrightarrow in math-
mode. But this is sometimes too short for me. Is there a way to
elongate a symbol in LaTeX? I don't feel like using an extra package
just because I want a longer \hookrightarrow, so if this is not
possible without the use of an extra package I'll just put up with
\hookrightarrow

LaTeX defines \hookrightarrow as \lhook\joinrel\rightarrow -- the
combination of a hook and a right arrow. It further defines
\longrightarrow
as \relbar\joinrel\rightarrow -- the combination of a line and a right
arrow. All you need to do is combine the three parts (hook, line, arrow)
\newcommand*{\longhookrightarrow}{\ensuremath{\lhook\joinrel\relbar\joinrel\rightarrow}}
-- Scott

I'd be interested in how for example \rightrightarrow 's are defined,
and how to be able to produce for example a \xrightrightarrow, as
obscure as that may sound.

Adrian

[Scott Pakin]

Post by Adrian Nievergelt
I'd be interested in how for example \rightrightarrow 's are defined,
and how to be able to produce for example a \xrightrightarrow, as
obscure as that may sound.

\rightrightarrows is a single character, not a combination of two
\rightarrow characters. amssymb.sty defines it with:

\DeclareMathSymbol{\rightrightarrows} {\mathrel}{AMSa}{"13}

Unfortunately, \Relbar doesn't line up nicely with \rightrightarrows so
you may be stuck employing a kludgy solution like the following, in which
one \relbar is raised, one is lowered, and enough negative horizontal
space is inserted to make the tails line up with the arrows:

\newcommand*{\longrightrightarrows}{%
\ensuremath{%
\makebox[0pt][l]{\raisebox{0.4ex}{\ensuremath{\relbar}}}%
\raisebox{-0.4ex}{\ensuremath{\relbar}}%
\hspace*{-0.5em}%
\rightrightarrows
}%
}

-- Scott