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I'm writing a document in LaTeX, but I can't figure out how I could write the circle symbol in order to indicate the composition of two linear maps, as LaTeX prints "error" when I compile the file. It's weird, as I have seen this in a math book, and I would like to write it in the same format in my file. Here you have what I've done so far:

\documentclass[a4paper,12pt]{article}
\usepackage{esvect}
\usepackage{amssymb}
\usepackage[utf8]{inputenc}
\usepackage[catalan]{babel}
\usepackage{enumerate}
\usepackage{color}
\usepackage{amsmath}
\usepackage{amsthm}
\newcommand{\matriu}[3]{M(#1,B_#2,B_#3)}
\newcommand{\vect}[2]{(#1_1,\dots ,#1_#2)}
\begin{document}
Siguin $B_1=\vect{u}{n}$ una base de $E_1$, $B_2=\vect{v}{m}$ una base de $E_2$ i                                            
$B_3=\vect{w}{s}$ una base de $E_3$. Llavors 
\begin{equation*} \matriu{f\circle g}{1}{2}=\matriu{g}{2}{3} \phantom{.} \matriu{f,1,2}     
\end{equation*}
\end{document}

Thank you very much for your attention and sorry for any inconvenience I may cause (I'm a newbie on LaTeX).

lockstep
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Sky
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    Welcome to TeX.sx! The command is \circ. – Corentin Mar 19 '13 at 16:13
  • Welcome to TeX.sx! – jub0bs Mar 19 '13 at 16:14
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    This question is very similar to Is there a circle symbol?. Please take a look at it as the information there might help you. If so, that's great, and we'll probably close this question as a duplicate just to keep the place tidy and to help people find answers quickly. If not, please edit your question here to explain why so that people can better focus their attention to help you. – egreg Mar 19 '13 at 16:20
  • There are two problems: First, use \circ instead of \circle. Second, replace \matriu{f,1,2} with \matriu{f}{1}{2}. – Mico Mar 19 '13 at 16:24
  • Yes, I see it's a duplicate, so you can close this question. Thanks for telling me! And yes, it works for \circ! By the way, thanks for spotting the \matriu mistake Mico, but it was just a mistake I had done while typing fast :) I hope you have a great day all of you! – Sky Mar 19 '13 at 16:48

0 Answers0