Borel's theorem
In topology, a branch of mathematics, Borel's theorem, due to Armand Borel (1953), says the cohomology ring of a classifying space or a classifying stack is a polynomial ring.
In topology, a branch of mathematics, Borel's theorem, due to Armand Borel (1953), says the cohomology ring of a classifying space or a classifying stack is a polynomial ring.