2011/03/27 by Yaroslav Kopylov, Kopylov, Yaroslav
Mathematics · #18E05 #Algebraic structures and combinatorial models #Category Theory (math.CT) #FOS: Mathematics #Homotopy and Cohomology in Algebraic Topology #Rings, Modules, and Algebras #math.CT #msc:18E05
paper · pdf · doi:10.48550/arxiv.1103.5251
10 pages
arxiv created 2011/03/27 · openalex publication_date 2011/03/27 · arxiv updated 2011/03/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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.