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arXiv · 1103.5251

The Two-Square Lemma and the connecting morphism

Yaroslav Kopylov
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Abstract

We obtain a generalization of the Two-Square Lemma proved for abelian categories by Fay, Hardie, and Hilton in 1989 and (in a special case) for preabelian categories by Generalov in 1994. We also prove the equivalence up to sign of two definitions of a connecting morphism of the Snake Lemma.

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Yaroslav Kopylov. 2011-03-27. The Two-Square Lemma and the connecting morphism. https://arxiv.org/abs/1103.5251

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