ArticleOriginal scientific text
Title
Maps on matrices that preserve the spectral radius distance
Authors 1, 2, 3
Affiliations
- Indian Statistical Institute, New Delhi 110 016, India
- Department of Mathematics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Department of Mathematics and Statistics, University of Victoria, Victoria, B.C., Canada V8W 3P4
Abstract
Let ϕ be a surjective map on the space of n×n complex matrices such that r(ϕ(A)-ϕ(B))=r(A-B) for all A,B, where r(X) is the spectral radius of X. We show that ϕ must be a composition of five types of maps: translation, multiplication by a scalar of modulus one, complex conjugation, taking transpose and (simultaneous) similarity. In particular, ϕ is real linear up to a translation.
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