Abstract (EN):
In this paper, we completely characterize the linear maps phi : M -> M that preserve the Lorentz-cone spectrum, when M is one of the following subspaces of the space M-n of n x n real matrices: the subspace of diagonal matrices, the subspace of block-diagonal matrices A circle plus [a], where A is an element of Mn-1 is symmetric, and the subspace of block-diagonal matrices A circle plus [a], where A is an element of Mn-1 is a generic matrix. In particular, we show that phi should be what we call a standard map, namely, a map of the form phi(A) = PAQ for all A is an element of M or phi(A) = PA(T)Q for all A is an element of M, for some matrices P, Q is an element of M-n. We then characterize the standard maps preserving the Lorentz-cone spectrum, when M is the subspace S-n of symmetric matrices. The case MIMn was considered in a recent paper by Seeger (LAA 2020). We include it here for completeness.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
20