The 
th
cohomology group of a cochain complex 
is 
. For a topological
space, singular cohomology is obtained by applying a coefficient-group hom
functor to its singular chain complex.
Cohomology Group
See also
Cochain Complex, Cohomology, Homology GroupExplore with Wolfram|Alpha
References
Hatcher, A. Algebraic Topology. Cambridge, England: Cambridge University Press, 2002.Cite this as:
Weisstein, Eric W. "Cohomology Group." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CohomologyGroup.html