Rizza manifold

The Rizza manifold is a specific example of a 5-dimensional smooth manifold that is characterized by having a nontrivial topology and a certain geometric structure. It was introduced by the mathematician Emil Rizza in a paper exploring exotic differentiable structures. One key feature of the Rizza manifold is that it is a counterexample in the study of differentiable manifolds, particularly in the context of 5-manifolds and their properties related to smooth structures.