# Average integral symbol

Is there in LaTeX a symbol or a macro for the average integral with a horizontal slash? I know about \strokedint, but I'd prefer the dash to be horizontal.

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Generally the first place to check for this kind of things is the Comprehensive LaTeX Symbol List ctan.org/tex-archive/info/symbols/comprehensive On page 71 it quotes the answer Vivi gives below and attributes it to the UK TeX FAQ. –  Willie Wong Aug 1 '10 at 13:02
I have to wonder why the Unicode guys called it "finite part"; this symbol is traditionally used for the "(Cauchy) principal value", while the "(Hadamard) finite part" usually has two bars crossing over the integral sign. –  user914 Aug 24 '10 at 14:56
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## 4 Answers

This answer probably will not help you right now, but it should sometime in the future.

There is a unicode entry for that symbol U+2A0D FINITE PART INTEGRAL: ⨍ (your computer might or might not display this correctly. At least modern Linux distros should). The STIX font and unicode-math seem to support that symbol, so if you have them set up you can just use the symbol. As Will Robertson remarked below, unicode-math provides the \intbar command to access the symbol.

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FWIW, the unicode-math name for this symbol is \intbar –  Will Robertson Aug 1 '10 at 14:16
Thanks. I guess I should have a good look at the unicode-math symbol list. –  Caramdir Aug 1 '10 at 14:41
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I found a solution here. You can use the following instructions, which must be included on the preamble.

\def\Xint#1{\mathchoice
{\XXint\displaystyle\textstyle{#1}}%
{\XXint\textstyle\scriptstyle{#1}}%
{\XXint\scriptstyle\scriptscriptstyle{#1}}%
{\XXint\scriptscriptstyle\scriptscriptstyle{#1}}%
\!\int}
\def\XXint#1#2#3{{\setbox0=\hbox{$#1{#2#3}{\int}$ }
\vcenter{\hbox{$#2#3$ }}\kern-.6\wd0}}
\def\ddashint{\Xint=}
\def\dashint{\Xint-}


The commands to execute those macros are \dashint and \ddashint for single dash and double dash, respectively.

EDIT: I tested the code given in the page, and the dash was a bit to the left of the integral, so I changed it slightly, substituting the .5 from the line \vcenter{\hbox{$#2#3$ }}\kern-.5\wd0}} with a .6 . It worked for me, if it doesn't exactly do it for you, experiment with the .5 to find exactly where you want the dash to be, adding (subtracting) from the number to place it more to the right (left).

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That solution is also on the UK TeX FAQ BTW (saying this because PlanetMath is sometimes flaky). –  ShreevatsaR Aug 1 '10 at 10:40
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There is a very useful site for this sort of questions. It is a hand-writing interface to the comprehensive LaTeX symbol list: you draw the symbol you are looking for in a box (using your mouse,...) and the software tries to recognise it. You can teach the software by telling it which one (if any) of its suggestions is the one you wanted.

I tried it with the average integral symbol and it suggested the command \fint in the esint package. That package seems to contain a number of ornamented integral signs.

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Quote from OP: > I know about \strokedint, but I'd prefer the dash to be horizontal. \fint also has the "wrong" direction of the slash. –  qbi Aug 1 '10 at 18:58
Oops -- somehow missed that. The offending line has been removed. At any rate, it might be useful to point out the Detexify website. –  José Figueroa-O'Farrill Aug 1 '10 at 23:30
The link to the Detexify LaTeX symbol classifier is useful for the general case of this problem. –  mas Jul 30 '11 at 12:16
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I'm not aware of a pre-existing version of that sign. So you have to design it for yourself. I would suggest something like:

\newcommand*{\avint}{\mathop{\ooalign{$\int$\cr$-$}}}


\ooalign vertically overlaps symbols. Internally it creates a tabular environment. Thatswhy you need the \cr between the $\int$ and $-$.

edit: This example compiles and shows the correct sign:

\documentclass{article}
\newcommand*{\avint}{\mathop{\ooalign{$\int$\cr$-$}}}
\begin{document}
$\avint_{i=0}^{\infty} f(x)dx$ or
$\giint_{i=0}^{\infty} f(x)dx$
\end{document}

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It doesn't work correctly in display mode or with limits. –  KennyTM Aug 1 '10 at 11:18
Can you give some minimal example or a log message? I added a minimal example to my answer above. –  qbi Aug 1 '10 at 19:02
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