splitting lemma
lemma 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 sum
en-US/ˈsplɪtɪŋ ˈlɛmə/
en-GB/ˈsplɪtɪŋ ˈlɛmə/
lemma 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 sum