Marcel Scherer

works on

calkin algebra 1 exactness 1 hyperrigidity 1 lifting property 1 operator systems 1 smith-ward problem 1

From the 1 of 9 linked papers with an AI index.

activity

20242026

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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.