Pontryagin Class
The ith Pontryagin class of a vector bundle is (-1)^i times the ith Chern class of the complexification of the vector bundle. It is also in the 4ith cohomology group of the base space involved.
See also
Chern Class, Stiefel-Whitney ClassExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Pontryagin Class." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PontryaginClass.html