Matrix Lie Groups as 3-Dimensional Almost Paracontact Almost Paracomplex Riemannian Manifolds

Hyperspheres in Euclidean and Minkowski 4-spaces as almost paracontact almost paracomplex Riemannian manifolds

“…An object of particular interest in our research is the case of the lowest dimension (which is three) of almost paracontact almost paracomplex Riemannian manifolds. In this regard, we study their properties in [7,8,9].…”