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2 votes

Why do all incidence theorems follow from Pappus' theorem?

There's a recent talk by Sergey Fomin about this topic exactly - Abstract: We show that various classical theorems of real/complex linear incidence geometry,...
Nick Ulyanov's user avatar
4 votes

Is the group of translations of an affine plane always commutative?

Let $G$ be an arbitrary countably-infinite group. I claim that there is an affine plane $X$ such that $\operatorname{Trans}(X)$ contains a subgroup isomorphic to $G$. By a back-and-forth argument one ...
user49822's user avatar
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