How to make new commands for function operations that don't italicize

Question

I created new commands for Galois groups and Automorphism groups like so,

\newcommand{\Gal}[1]{\text{Gal}(#1)}
\newcommand{\Aut}[1]{\text{Aut}(#1)}

I wanted to the text of Gal and Aut to be unitalicized and that works for normal math mode, but it italicizes in theorem environments. How can I keep it from italicizing in theorems and propositions?

An example of a function that does what I want would be the gcd function.

Answer 1

I suppose you load amsmath or mathtools. This is the way:

\DeclareMathOperator{\Gal}{Gal}
\DeclareMathOperator{\Aut}{Aut}

Not only will it not be italicised, but you'll get a correct spacing for exponents, indices, &c.