Essential manifolds with extra structures

Abstract

We consider classes of algebraic manifolds $\mathcal{A}$, of symplectic manifolds $\mathcal{S}$, of symplectic manifolds with the hard Lefschetz property $\mathcal{HS}$ and the class of cohomologically symplectic manifolds $\mathcal{CS}$. For every class of manifolds $\mathcal{C}$ we denote by $\mathcal{EC}(π,n)$ a subclass of $n$-dimensional essential manifolds with fundamental group $π$. In this paper we prove that for all the above classes with symplectically aspherical form the condition $\mathcal{EC}(π,2n)\ne \emptyset$ implies that $\mathcal{EC}(π,2n-2)\ne\emptyset $ for every $n>2$. Also we prove that all the inclusions $\mathcal{EA}\subset\mathcal{EHS}\subset\mathcal{ES}\subset\mathcal{ECS}$ are proper.