Rational Homology 5-Spheres with Positive Ricci Curvature
Rational Homology 5-Spheres with Positive Ricci Curvature
We prove that for every integer k>1 there is a simply connected rational homology 5-sphere M 5 k with spin such that H 2 (M 5 k ,Z) has order k 2 , and M 5 k admits a Riemannian metric of positive Ricci curvature.Moreover, if the prime number decomposition …