14 citations · 25 across the 15 of their papers we have counts for
19 papers
Addendum to "Factoring non-negative operator valued trigonometric polynomials in two variables"
Michael A. Dritschel, Igor Klep, Scott McCullough +1
Factorization for positive semidefinite matrix-valued polynomials over a nonsingular compact affine real surface is established. Corollaries include Fejér-Riesz factorization for b…
Hermitian indices and factorization of selfadjoint operators on a Kreĭn space
Michael A. Dritschel, Alejandra Maestripieri, James Rovnyak
The hermitian indices of a selfadjoint operator on a Kreĭn space are defined as geometric measures of positivity and negativity of the operator. A different pair o…
Rearrangement Invariant Orthogonal Sums in Krein Spaces. II
Michael A. Dritschel, Alejandra Maestripieri, James Rovnyak
Part I of the paper considered infinite orthogonal sums of regular subspaces in a Krein space (that is, of subspaces which are themselves Krein spaces). How precisely these sums sh…
Products of positive operators
Maximiliano Contino, Michael A. Dritschel, Alejandra Maestripieri +1
On finite dimensional spaces, it is apparent that an operator is the product of two positive operators if and only if it is similar to a positive operator. Here, the class ${\mathc…
Factoring Non-negative Operator Valued Trigonometric Polynomials in Two Variables
Michael A. Dritschel
It is shown using Schur complement techniques that on finite dimensional Hilbert spaces, a non-negative operator valued trigonometric polynomial in two variables with degree $(d_1,…
Rational dilation problems associated with constrained algebras
Michael A. Dritschel, Batzorig Undrakh
It is shown that rational dilation fails on broad collection of distinguished varieties associated to constrained subalgebras of the disk algebra of the form C + B A(D), where B is…