On Ehresmann semigroups

Mark V Lawson

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arXiv · 2102.12250

On Ehresmann semigroups

Mark V Lawson

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Abstract

We formulate an alternative approach to describing Ehresmann semigroups by means of left and right \'etale actions of a meet semilattice on a category. We also characterize the Ehresmann semigroups that arise as the set of all subsets of a finite category. As applications, we prove that every restriction semigroup can be nicely embedded into a restriction semigroup constructed from a category, and we describe when a restriction semigroup can be nicely embedded into an inverse semigroup.

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Mark V Lawson. 2021-02-24. On Ehresmann semigroups. https://arxiv.org/abs/2102.12250

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