Monthly Archives: July 2013

Hyperplane face semigroups and zonotopes

Hyperplane face semigroups have attracted interest in recent years due to applications to Markov chains, descent algebras and buildings. Here I’ll describe an alternative way to think about hyperplane face semigroups from the zonotope view point.

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Endomorphism monoids of finite topological spaces

This post is inspired by this Mathoverflow question. The question asks when a transformation monoid on a set can be the monoid of all continuous maps for some topology on . The OP observes that the monoid must contain all … Continue reading

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Combinatorics on Words

I am recording here some neat proofs of some theorems on combinatorics on words. No great originality is claimed.

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