A half-line of Schur idempotent norms

Rupert H. Levene

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arXiv · 2611.08419

A half-line of Schur idempotent norms

Rupert H. Levene

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Abstract

Using a family of bipartite graphs constructed by hanging identical rooted trees at every vertex of a highly symmetric graph, we show that every sufficiently large real number is the norm of an idempotent Schur multiplier on the bounded operators on $\ell^2$. This answers a question previously raised by the author.

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Rupert H. Levene. 2026-11-05. A half-line of Schur idempotent norms. https://arxiv.org/abs/2611.08419

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