
When is one thing equal to some other thing? (2007) [pdf] - aptidude187
http://www.math.harvard.edu/~mazur/preprints/when_is_one.pdf
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johnday
What a fun, accessible and well-presented paper. I'm not sure who Saunders
MacLane is but their memory is served well.

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adamnemecek
Co-founder of category theory.

