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arXiv · 1311.2974

The other pullback lemma

Michal R. Przybylek
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Abstract

Given a composition of two commutative squares, one well-known pullback lemma says that if both squares are pullbacks, then their composition is also a pullback; another well-known pullback lemma says that if the composed square is a pullback and the supporting square is a pullback, then the other square is a pullback as well. This note investigates the third of the possibilities.

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Michal R. Przybylek. 2014-10-05. The other pullback lemma. https://arxiv.org/abs/1311.2974

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