activity
20062026
most citedConnes' embedding conjecture and sums of hermitian squares

116 citations · 1.1k across the 72 of their papers we have counts for

collaborators

75 papers

math.OC2026

Convergence Rates for Lasserre's Upper-Bound Hierarchy on with Gaussian Measure

Sander Gribling, Igor Klep, Poornendu Kumar

We establish quantitative convergence rates for Lasserre's measure-based upper-bound hierarchy on using the standard Gaussian measure as the reference measure. For a…

math.FA2026

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…

quant-ph2026

Quantitative semidefinite certificates for ground-state energies of Pauli Hamiltonians

Igor Klep, Nando Leijenhorst, Victor Magron

The -local Hamiltonian problem is a central model for quantum many-body systems and Hamiltonian complexity. Semidefinite programming and noncommutative sum-of-squares hierarchie…

math.FA2026

Operator-Valued Positivstellensätze on Matrix Convex Sets and Free Products of Finite Abelian Groups

Abhay Jindal, Igor Klep, Scott McCullough

We prove a Positivstellensatz for operator-valued noncommutative polynomials that are positive on matrix convex sets. Specifically, let be an operator-valued polynomial in $B(H…

math.FA2025

Fejér--Riesz factorization for positive noncommutative trigonometric polynomials

Igor Klep, Jacob Levenson, Scott McCullough

We prove a Fejér-Riesz type factorization for positive matrix-valued noncommutative trigonometric polynomials on , where is either the…

math.FA2025

Positive operator-valued noncommutative polynomials are squares

Abhay Jindal, Igor Klep, Scott McCullough

We establish operator-valued versions of the earlier foundational factorization results for noncommutative polynomials due to Helton (Ann.~Math., 2002) and one of the authors (Line…