Has anyone seen $N(M)$ in the context of linear algebra/matrix notation?

Question

To be honest, I can't shed too much context other than that it's related to matrices, as this is some feint memory for a test I did a few months ago.

I wrote down after the test certain notation which was used, such as det(M) and adj(M) (obviously know what these are).

I also have $N(M)$ written down, where $M$ is the matrix, but can't for the life of me determine what this could mean?

Does anyone have any idea, or did I probably just write it down wrong. Is there a common list of matrix notation somewhere?

Thanks

Answer 1

In some books, $N(M)$ or $\mathcal N(M)$ is used to mean "the nullspace (kernel) of $M$". By the same token, $R(M)$ or $\mathcal R(M)$ is used to mean "the range (image) of $M$".