this is an easy question, but I couldn't find the answer just from other similar questions.
A lot of people often get an error in the form:
LaTeX Error: Command \XYZ already defined.
Or name \end... illegal, see p.192 of the manual.
usually, the problem is that they are using something that is defined in 2 different packages, so LaTeX is confused about what to do with the command.
My symptoms are similar:
after lines
88 \begin{definition}
89 The distribution of a random variable $X$ is usually described by giving its {\bf distribution function}, $f(x) = P(X \leq x)$.
90 \end{definition}
my TeXShop is saying:
89:LaTeX Error: Command \c@T already defined.
Or name \end... illegal, see p.192 of the manual.
So, I tried to find where could command \c@T be defined. I'm only using
\usepackage{amssymb,amsmath}
\usepackage{changepage}
and I don't really see how they could both define command c@T.
I looked at the list of all commands in LaTeX, at http://www-sop.inria.fr/marelle/tralics/doc-c.html#cmd-citetype, and I haven't even found such command, but it looked like some kind of counting is the problem. So, I admit that I also have
\begin{document}
\newenvironment{definition}[1][Definition]
\newcounter{definition}
which might be the place where I defined something in the wrong way, but I don't see why wouldn't this problem come up in the previous definitions.
If anyone had patience to solve this old problem again and explain it to me, I would really appreciate it.
Best Answer
What's apparently happening is the following: as @Ulrike remarks, your
\newenvironment
lacks its two mandatory arguments. It will instead pick up\newcounter
anddefinition
, since that is what follows.What this does is that when you call
\begin{definition}
, you inadvertently call\newcounter
, soturns into, with some technicalities omitted,
i.e.
and that's where your counters come from and that's why you get an error: you probably have to definitions that start with "T"!
(To backtrack and solve your problem: I think you really mean to look at the amsthm package and its
\newtheorem
command?)