A cohomology class is an element of a cohomology group. In a cochain complex it is represented by a cocycle, with two cocycles representing the same class when their difference is a coboundary. Geometric structures such as vector bundles and differential forms often determine characteristic cohomology classes.
Cohomology Class
See also
Cochain Complex, Cohomology Group, Differential k-FormExplore with Wolfram|Alpha
References
Hatcher, A. Algebraic Topology. Cambridge, England: Cambridge University Press, 2002.Cite this as:
Weisstein, Eric W. "Cohomology Class." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CohomologyClass.html