It seems a lot of impossibility theorems - the type that the ancient Greeks would have understood - can be proven using algebraic topology. Perhaps Sperner's lemma can be seen as an algebraic topology theorem? I don't personally know.
I think the last word in that sentence should be "finite"?
Also do I understand correctly that "face" means "maximal line segment"? (I see some other comments discussing this and concluding that "face" means "edge", but to me, an "edge" doesn't permit "intermediate" vertices.)
prof-dr-ir•4h ago
That should be 'edge', not 'face', no? Otherwise I do not understand what is happening at all with the examples.
erooke•3h ago
dmurray•3h ago