Displaying similar documents to “The densest packing of 13 congruent circles in a circle.”

On separation of eigenvalues by the permutation group

Grega Cigler, Marjan Jerman (2014)

Special Matrices

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Let A be an invertible 3 × 3 complex matrix. It is shown that there is a 3 × 3 permutation matrix P such that the product PA has at least two distinct eigenvalues. The nilpotent complex n × n matrices A for which the products PA with all symmetric matrices P have a single spectrum are determined. It is shown that for a n × n complex matrix [...] there exists a permutation matrix P such that the product PA has at least two distinct eigenvalues.