| Abstrakt: |
We show that for each n\geqslant 1, there exist infinitely many spin and non-spin diffeomorphism types of closed, smooth, simply-connected (n + 4)-manifolds with a smooth, effective action of a torus Tn+2 and a metric of positive Ricci curvature invariant under a Tn-subgroup of Tn+2. As an application, we show that every closed, smooth, simply-connected 5- and 6-manifold admitting a smooth, effective torus action of cohomogeneity two supports metrics with positive Ricci curvature invariant under a circle or T2-action, respectively. [ABSTRACT FROM AUTHOR] |
