Perspectives on categories.

Category theory is a very fascinating area of mathematics. It's unexpectedly powerful in an incredible width of different contexts, from the purest abstractions to the most concrete applications. I'm far from being an expert in category theory, although I enjoy fiddling with it and looking through the categorical lens at the material of my courses. … Continue reading Perspectives on categories.

A game with AC, plus the story of a poster.

Today I stumbled upon an interesting article about a 'paradoxical' appearance of the axiom of choice in a generalization of the known 'hats on prisoners' puzzle. Two Three interesting thing in the linked page: The generalization of the game: multiple colours, infinite prisoners. I also guess ultrafilters appear, in disguise, when talking equivalences on infinite … Continue reading A game with AC, plus the story of a poster.