How to Add the arg max and arg min Functions to Lyx

October 30, 2011 by Brian D'Alessandro

The arg max and arg min functions are not standard as math functions in LaTeX. As a result, they are not straightforward to use in Lyx either. However, it is quite simple to do so:

1. Add the following code to the LaTeX preamble in Lyx (Document > Settings > LaTeX Preamble):

\usepackage{amsmath}
\DeclareMathOperator*{\argmax}{arg\,max}
\DeclareMathOperator*{\argmin}{arg\,min}

2. When you create a new math field in Lyx, simply type \argmax or \argmin. You can follow it by an underscore if you need text below the arg max or arg min functions. This text will be centered across all six letters.

It's that simple!