We continue to study Pythagorean unitary representations of Richard Thompson’s groups F; T; V and their extension to the Cuntz(–Dixmier) algebra O. Any linear isometry from a Hilbert space to its direct sum square produces such. We focus on those arising from a finite-dimensional Hilbert space. We show that they decompose as a direct sum of a so-called diffuse part and an atomic part. We previously proved that the diffuse part is Ind-mixing: it does not contain induced representations of finite-dimensional ones. In this article, we fully describe the atomic part it is a finite direct sum of irreducible monomial representations arising from a precise family of parabolic subgroups.
Atomic representations of R. Thompson’s groups and Cuntz’s algebra / Brothier, Arnaud; Wijesena, Dilshan. - In: DOCUMENTA MATHEMATICA. - ISSN 1431-0635. - 31:2(2026), pp. 355-383. [10.4171/dm/1031]
Atomic representations of R. Thompson’s groups and Cuntz’s algebra
Brothier, Arnaud;
2026-01-01
Abstract
We continue to study Pythagorean unitary representations of Richard Thompson’s groups F; T; V and their extension to the Cuntz(–Dixmier) algebra O. Any linear isometry from a Hilbert space to its direct sum square produces such. We focus on those arising from a finite-dimensional Hilbert space. We show that they decompose as a direct sum of a so-called diffuse part and an atomic part. We previously proved that the diffuse part is Ind-mixing: it does not contain induced representations of finite-dimensional ones. In this article, we fully describe the atomic part it is a finite direct sum of irreducible monomial representations arising from a precise family of parabolic subgroups.Pubblicazioni consigliate
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