What is the Modulus of a Matrix? I came across the following:
"Let f be continuously differentiable with Lipschitz gradient, i.e.,
$ ||\nabla f(\mathbf{x}) - \nabla f(\mathbf{y})|| \leq L||(\mathbf{x} - \mathbf{y})|| $
where L is the modulus of the Hessian (if exists)."
What is the modulus of a matrix? Is it the same thing as the determinant?
Thanks!

As linear operator $\nabla f$ has a so-called operator norm. In your case this is $L$
