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arXiv · 2101.00244

Central and convolution Herz-Schur multipliers

Andrew McKee·Reyhaneh Pourshahami·Ivan G. Todorov·Lyudmila Turowska
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Abstract

We obtain descriptions of central operator-valued Schur and Herz-Schur multipliers, akin to a classical characterisation due to Grothendieck, that reveals a close link between central (linear) multipliers and bilinear multipliers into the trace class. Restricting to dynamical systems where a locally compact group acts on itself by translation, we identify their convolution multipliers as the right completely bounded multipliers, in the sense of Junge-Neufang-Ruan, of a canonical quantum group associated with the underlying group. We provide characterisations of contractive idempotent operator-valued Schur and Herz-Schur multipliers. Exploiting the link between Herz-Schur multipliers and multipliers on transformation groupoids, we provide a combinatorial characterisation of groupoid multipliers that are contractive and idempotent.

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Andrew McKee, Reyhaneh Pourshahami, Ivan G. Todorov, Lyudmila Turowska. 2021-01-01. Central and convolution Herz-Schur multipliers. https://arxiv.org/abs/2101.00244

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