Atiyah–Bott formula

In algebraic geometry, the Atiyah–Bott formula says the cohomology ring

${\displaystyle \operatorname {H} ^{*}(\operatorname {Bun} _{G}(X),\mathbb {Q} _{l})}$

of the moduli stack of principal bundles is a free graded-commutative algebra on certain homogeneous generators. The original work of Michael Atiyah and Raoul Bott concerned the integral cohomology ring of ${\displaystyle \operatorname {Bun} _{G}(X)}$.