Alejandro Varela

collaborators

2 papers

math.FA2026

Best approximants relative to a C $^{*}$ -subalgebra, joint numerical range and subdifferentials

Tamara Bottazzi, Alejandro Varela

We study the minimality of $n \times n$ Hermitian matrices $A$ respect to a $C^{*}$ -subalgebra $B$ of $M_{n} (C)$ in the spectral norm, that is \[\|A\|\leq \|A+B\|,\ \…

math.FA2024

Minimal compact operators, subdifferential of the maximum eigenvalue and semi-definite programming

Tamara Bottazzi, Alejandro Varela

We formulate the issue of minimality of self-adjoint operators on a Hilbert space as a semi-definite problem, linking the work by Overton in [1] to the characterization of minimal…

Best approximants relative to a C∗-subalgebra, joint numerical range and subdifferentials

Minimal compact operators, subdifferential of the maximum eigenvalue and semi-definite programming

Best approximants relative to a C $^{*}$ -subalgebra, joint numerical range and subdifferentials