We introduce the notions of relational groupoids and relational convolution algebras. We provide various examples arising from the group algebra of a group G and a given normal subgroup H. We also give conditions for the existence of a Haar system of measures on a relational groupoid compatible with the convolution, and we prove a reduction theorem that recovers the usual convolution of a Lie groupoid.
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© 2021. Pacific Journal of Mathematics. All rights reserved.
- convolution algebra
- Haar systems
- Lie groupoids
- relational groupoids