Rigidity in sharp eigenvalue estimates for differential forms
For $1\leq p\leq n/2$, we derive sharp eigenvalue estimates for the Hodge Laplacian on differential $p$-forms under the curvature condition introduced by Petersen and Wink, and study their equality cases. Equality recovers the stronger curvature operator lower bound and, in the closed case, leaves only round or Sasakian metrics on the universal cover. For manifolds with boundary, weak $p$-convexity of the boundary makes the unit hemisphere the only equality case for the absolute boundary problem.
math.DG↗