18-XX Category theory; homological algebra {For commutative rings, see 13Dxx; for associative rings, see 16Exx; for groups, see 20Jxx; for topological groups and related structures, see 57Txx; for algebraic topology, see also 55Nxx, 55Uxx} 36702
18E13 Protomodular categories, semi-abelian categories, Mal’tsev categories [See also 08B05 and 08B10] 98