2022/04/22 by Mateo Tomašević, Tomašević, Mateo
Mathematics · #Advanced Topics in Algebra #Graph theory and applications #Algebraic structures and combinatorial models
paper · pdf · doi:10.48550/arxiv.2204.11622
We prove that all injective maps on positive complex matrices which preserve order and shrink spectrum are implemented by unitary or antiunitary conjugations. We show by counterexamples that all assumptions are indispensable. The result easily generalizes to maps on hermitian matrices.