The Petersen--Wilhelm conjecture on principal bundles

Abstract: This paper studies Cheeger deformations on $\mathrm{S}^3, \mathrm{SO}(3)$ principal bundles to obtain conditions for positive sectional curvature submersion metrics. We conclude, in particular, a stronger version of the Petersen--Wilhelm fiber dimension conjecture to the class of principal bundles. We prove any $\pi: \mathrm{SO}(3), \mathrm{S}^3 \hookrightarrow \cal P \rightarrow B$ principal bundle over a positively curved base admits a metric of positive sectional curvature if, and only if, the submersion is fat, in particular, $\dim B \geq 4$. The proof combines the concept of ``good triples'' due to Munteanu and Tapp \cite{tappmunteanu2}, with a Chaves--Derdzisnki--Rigas type condition to nonnegative curvature. Additionally, the conjecture is verified for other classes of submersions.