Cohomology
From Conservapedia
In category theory, the cohomology of an exact sequence studies the relationship between the cokernels and coimages, when it is possible to take their quotient. Cohomology is the category-theoretic dual of homology.
Well-known examples include de Rham cohomology in differential geometry, elliptic cohomology, equivariant cohomology, and hyperbolic cohomology of infinite Abelian groups.