Abstract:
Let $K$ be a nonsingular skew-symmetric matrix of an even order $n = 2m$. For such a matrix, we propose a finite algorithm, using only arithmetic operations and quadratic radicals, for calculating an $m$-dimensional neutral subspace. The necessity of calculating neutral subspaces originates in the problem of solving quadratic matrix equations.
Key words and phrases:skew-symmetric matrix, $J$-symmetric matrix, symplectic matrix, Van Loan's algorithm.