# How to express “null T” in math mode [duplicate]

What is the correct way to express "null T", which represents the nullspace of a linear map T?

I've been doing \newcommand{\nullspace}{\text{null }} which is a hack, but I want there to be a space between "null" and "T".

One problem with my approach is that the "null" is italic when it's written within a theorem etc, but in a standard express it's not italic. I would prefer it to always be non-italic.

• How about \usepackage{amsmath} \DeclareMathOperator*{\nullspace}{null} – Steven B. Segletes Dec 29 '17 at 2:54

\documentclass{article}
$$\nullspace T$$
blah $\nullspace T$