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arXiv · 1901.03266

Categories of Two-Colored Pair Partitions, Part II: Categories Indexed by Semigroups

Alexander Mang·Moritz Weber
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Abstract

Within the framework of unitary easy quantum groups, we study an analogue of Brauer's Schur-Weyl approach to the representation theory of the orthogonal group. We consider concrete combinatorial categories whose morphisms are formed by partitions of finite sets into disjoint subsets of cardinality two; the points of these sets are colored black or white. These categories correspond to "half-liberated easy" interpolations between the unitary group and Wang's quantum counterpart. We complete the classification of all such categories demonstrating that the subcategories of a certain natural halfway point are equivalent to additive subsemigroups of the natural numbers; the categories above this halfway point have been classified in a preceding article. We achieve this using combinatorial means exclusively. Our work reveals that the half-liberation procedure is quite different from what was previously known from the orthogonal case.

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Alexander Mang, Moritz Weber. 2019-01-10. Categories of Two-Colored Pair Partitions, Part II: Categories Indexed by Semigroups. https://arxiv.org/abs/1901.03266

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