# Enumerate replaces uppercase letter 'A' with numbers?

When I try to do:

\documentclass{amsart}
\usepackage{enumerate}

\begin{document}

\begin{enumerate}[(A1)]
\item blah
\item blah blah
\end{enumerate}

\end{document}


I get the output of:

(11) blah
(22) blah blah


It seems to work fine with other uppercase letters, but I specifically need the capital letter 'A' for this list. How can I fix it?

• Read the documentation: "however the tokens A a I i 1 must be inside a { } group if they are not to be taken as special." – Ulrike Fischer Sep 24 '14 at 12:34

## 1 Answer

The output is indeed a bit surprising*, as I would have expected it to be:

(A1) blah

(B2) blah blah

I would have expected this, as the input of \begin{enumerate}[...] introduces the counting variable for your list and in fact you gave it two counting variables.

The possible active characters here are

• I for capital Roman numbers
• i for small Roman numbers
• 1 for Arabic numbers
• A for capital letters
• a for small letters

The last active character in your command wins. I do not know where the second number comes from. All other characters get ignored such as your parenthesis or the "other uppercase letters".

If you want enumerate to ignore one of the 5 active characters, you have to wrap it in curly braces.

% arara: pdflatex

\documentclass{amsart}
\usepackage{enumerate}

\begin{document}
\begin{enumerate}[({A}1)]
\item blah
\item blah blah
\end{enumerate}
\end{document}


*I contacted the maintainer of this package and here is Mr. Carlisle comment:

You get 11, 22 because each of the special letters gets turned into \theenumi and defines that to be (say) \alph{enumi}. So for A1 you get \theenumi\theenumi and define \theenumi to be \alph then \arabic so the latter definition wins but you still get two counters printed.

• \begin{enumerate}[label=(A\arabic*)] would be the syntax with enumitem. Clearer and less error prone. – egreg Sep 24 '14 at 13:16