How to create my own math operator with limits?

Question

How can i write my own math operator with limits? I want it to look like: \sum\limits_{e=1}^{m} but with a capital A (if possible bigger than the normal text) instead of the sum. Thanks for the help!

Answer 1

Use \mathop to turn A into a "math operator", and then use \limits to do sum-style limits:

 $$\mathop{A}\limits_{e=1}^{m}$$

Do you really want A, or do you want \bigwedge?

Answer 2

Use the \DeclareMathOperator* command provided by the amsmath package. Example:

\documentclass{article}
\usepackage{amsmath}
\DeclareMathOperator*{\Aop}{A}
\begin{document}
\[ \Aop^a_b \]
\end{document}

Answer 3

\newcommand{\opA}{\mathop{\vphantom{\sum}\mathchoice
  {\vcenter{\hbox{\huge A}}}
  {\vcenter{\hbox{\Large A}}}{\mathrm{A}}{\mathrm{A}}}\displaylimits}

In this way the "A" will be as large as the \sum symbol.

Answer 4

\documentclass{article}
\usepackage{amsmath}
\def\Aop{\operatornamewithlimits{%
  \mathchoice{\vcenter{\hbox{\huge A}}}
             {\vcenter{\hbox{\Large A}}}
             {\mathrm{A}}
             {\mathrm{A}}}}
\begin{document}

\[ \Aop^a_b \sum_a^b \]

$ \Aop^a_b \sum_a^b $

\end{document}