Marcel Scherer

activity

20242026

collaborators

5 papers

math.OA2026

The Hyperrigidity Conjecture for Spectrahedra

Marcel Scherer

We show that if K is a compact spectrahedron whose set of extreme points is closed, then the operator system of continuous affine functions on K is hyperrigid in the C*-algebra C(e…

math.OA2026

A C*-cover lattice dichotomy

Adam Humeniuk, Christopher Ramsey, Marcel Scherer

In this paper, we show that the lattice of C*-covers of a non-selfadjoint operator algebra is either one point or uncountable. We prove that there are non-selfadjoint operator alge…

math.FA2025

The SOT-closure of the set of 2-isometries

Marcel Scherer

We show that the set of $2$ -isometries on an infinite-dimensional Hilbert space is not closed in the strong operator topology. In fact, we prove that its SOT-closure coincides with…

math.FA2025

A Finite Dimensional Counterexample for Arveson's Hyperrigidity Conjecture

Marcel Scherer

We construct an operator system generated by $4$ operators that is not hyperrigid, although all restrictions of irreducible representations have the unique extension property.

math.FA2024

The Hyperrigidity Conjecture for compact convex sets in $R^{2}$

Marcel Scherer

We prove that for every compact, convex subset $K \subset R^{2}$ the operator system $A (K)$ , consisting of all continuous affine functions on $K$ , is hyperrigid in the C*-alge…

The Hyperrigidity Conjecture for Spectrahedra

A C*-cover lattice dichotomy

The SOT-closure of the set of 2-isometries

A Finite Dimensional Counterexample for Arveson's Hyperrigidity Conjecture

The Hyperrigidity Conjecture for compact convex sets in R2

The Hyperrigidity Conjecture for compact convex sets in $R^{2}$