Structures of generalized 3-circular projections for symmetric norms (Q282327)

Structures of generalized bi-circular projections in spaces, where the descriptions of the group of surjective isometries are known, were recently investigated by several authors. Following the same approach, in the present paper, a complete description of generalized 3-circular projections for symmetric norms on \(\mathbb C^n\) and \(\mathbb M_{m\times n}(\mathbb C)\) is given. The structure of generalized 3-circular projections for a~symmetric norm that is not a~multiple of an inner-product norm on \(\mathbb C^n\) up to permutation similarity is identified.