De Rham cohomology of algebraic varieties : for affine varieties, this is theorem 1 below, and it implies a theorem for general algebraic schemes.

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mathematicians ran out of numbers in the 1700s. since then they've been attempting to pass letters and symbols off as numbers, with varying success

I've been thinking about the fact that an n×n square grid has as many cells as a triangular lattice with n triangles on each side.
Is there a nice continuous bijection between them? When n is odd, you can at least keep one line of symmetry throughout.

If you're going to be pedantic about the new decade starting in 2021 because "there was no year 0", then you also have to be pedantic about the new decade starting on January 11, 2021, because there were no October 5-14, 1582. :steven_pun:

This is the (co)end, my only (co)friend
Article by Loregian, Fosco
In collection: Attention-grabbing titles
The present note is a recollection of the most striking and useful applications of co/end calculus. We put a considerable effort in making arguments and constructions rather explicit: after having given a series of preliminary definitions, we...
Entry: read.somethingorotherwhatever.

Puzzle of the day: find a number that is a perfect square with exactly 300 times the digit 1 and where all other digits are 0.

I'll answer to the toot and give a solution there.

To ask is a temporary shame, not to ask a life-long shame -- Japanese proverb

time to crack on with some more EGA proofreading :qed:


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