18Gxx Homological algebra

18G05  Projectives and injectives, See also {13C10, 13C11, 16D40,
               16D50}
18G10  Resolutions; derived functors, See also {18E25}
18G15  Ext and Tor, generalizations, Kunneth formula, See Also {
               55U25}
18G20  Homological dimension, See also {13D05, 16E10}
18G25  Relative homological algebra, projective classes
18G30  Simplicial sets, simplicial objects (in a category), See
               also {55U10}
18G35  Chain complexes, See also {18E30, 55U15}
18G40  Spectral sequences, hypercohomology, See also {55Txx}
18G50  Nonabelian homological algebra
18G55  Nonabelian homotopical algebra
18G60  Other (co)homology theories (cyclic, dihedral, etc.), See
               also {19D55, 46L80, 58B30, 58G12}
18G99  None of the above but in this section