Pro-$p$ Poincaré-Duality groups of infinite rank

We introduce the class of $\mathit{\text{Generalized}}\mathit{\text{Poincar}}\acute{\mathit{\text{e}}}\mathit{\text{-Duality}}\mathit{\text{groups}}$: i.e, pro-$p$ groups of infinite rank which satisfy a Poincaré-duality. We prove some basic properties of Generalized Poincaré-Duality groups, and show that under some conditions, a group that fits into an exact sequence of GPD groups must be a Demushkin group.