The many mathematical faces of Mermin's proof of the Kochen-Specker theorem

Mermin’s simple “pentagram” proof of the Kochen-Specker theorem is examined from various perspectives. We emphasise the many mathematical structures intimately related to Kochen-Specker proofs, ranging through functional analysis, sheaf theory and topos theory, Coxeter groups and algebraic geometry. Some novel results are presented along the way.