(frame decoration) with an arrow tip. As far as I could search in the document recommended by you, such a bracket does not exist in LaTeX.
Paul - did you mean something like \underset{\{\}}{\rightarrow} ?? You can get this while in math mode by typing \underset and then inserting the appropriate entries..
No, Nirmal. I mean the following:
$$\underbracket[0.7pt][1em]{\mathbb{R}\longrightarrow\mathbb{R}}$$
You need to add the following to the preamble:
\def\underbracket{%
[EMAIL PROTECTED] [ %
[EMAIL PROTECTED]
[EMAIL PROTECTED] [EMAIL PROTECTED]
}
[EMAIL PROTECTED]
[EMAIL PROTECTED] [ %
[EMAIL PROTECTED]@bracket[#1]}%
[EMAIL PROTECTED]@bracket[#1][0.4em]}%
}
[EMAIL PROTECTED]@bracket[#1][#2]#3{%\message {Underbracket: #1,#2,#3}
\mathop {%
\vtop {%
[EMAIL PROTECTED] \ialign {%
##\crcr $\hfil \displaystyle {#3}\hfil $%
\crcr \noalign %
{\kern 3\p@ \nointerlineskip }%
\upbracketfill {#1}{#2}
\crcr \noalign %
{\kern 3\p@ }%
}%
}%
}%
\limits%
}
\def\upbracketfill#1#2{%
[EMAIL PROTECTED] \setbox \z@ \hbox {$\braceld$}
[EMAIL PROTECTED]@}\bracketend{#1}{#2}
\leaders \vrule [EMAIL PROTECTED] #1 [EMAIL PROTECTED] \z@ \hfill
\leaders \vrule [EMAIL PROTECTED] #1 [EMAIL PROTECTED] \z@ \hfill%
\bracketend{#1}{#2}$%
}
\def\bracketend#1#2{\vrule height #2 width #1\relax}