Isometry-invariant geodesics and nonpositive derivations of the cohomology

Abstract

We introduce a new class of artinian weighted complete intersections, by abstracting the essential features of Q-cohomology algebras of equal rank homogeneous spaces of compact connected Lie groups. We prove that, on a 1-connected closed manifold M with H*(M,Q) belonging to this class, every isometry has a nontrivial invariant geodesic, for any metric on M. We use Q-surgery to construct large classes of new examples for which the above result may be applied.