EntityQ2757856· pop 7· linked from 24 articlessplitting lemmaSign in to savelemma that, in an Abelian category, a short exact sequence, one of whose two morphisms admits a section or retraction into the middle term, is a direct sumConnectionsorderEntitymathematicsEntityInternational Standard Book NumberEntitylinear algebraEntitymathematical proofEntitypermutationEntityisomorphismEntityintersectionEntitybijectionEntityinjectionEntitysurjective functionEntitycategory theoryEntityidentity functionEntityimageEntityhomological algebraEntitygroup homomorphismEntitycyclic groupEntitynormal subgroupEntitySaunders Mac LaneEntitykernelEntityCategoriesHomological algebraLemmas in category theory