English

Generic canonical forms for perplectic and symplectic normal matrices

Rings and Algebras 2020-07-14 v2 Numerical Analysis Numerical Analysis

Abstract

Let BB be some invertible Hermitian or skew-Hermitian matrix. A matrix AA is called BB-normal if AA=AAAA^\star = A^\star A holds for AA and its adjoint matrix A:=B1AHBA^\star := B^{-1}A^HB. In addition, a matrix QQ is called BB-unitary, if QHBQ=BQ^HBQ = B. We develop sparse canonical forms for nondefective (i.e. diagonalizable) J2nJ_{2n}-normal matrices and RnR_n-normal matrices under J2nJ_{2n}-unitary (RnR_n-unitary, respectively) similarity transformations where J2n=[InIn]M2n(C)J_{2n} = \begin{bmatrix} & I_n \\ - I_n & \end{bmatrix} \in M_{2n}(\mathbb{C}) and RnR_n is the n×nn \times n sip matrix with ones on its anti-diagonal and zeros elsewhere. For both cases we show that these forms exist for an open and dense subset of J2n/RnJ_{2n}/R_n-normal matrices. This implies that these forms can be seen as topologically 'generic' for J2n/RnJ_{2n}/R_n-normal matrices since they exist for all such matrices except a nowhere dense subset.

Keywords

Cite

@article{arxiv.2006.16790,
  title  = {Generic canonical forms for perplectic and symplectic normal matrices},
  author = {Ralph John de la Cruz and Philip Saltenberger},
  journal= {arXiv preprint arXiv:2006.16790},
  year   = {2020}
}
R2 v1 2026-06-23T16:44:10.019Z