Are there any known types of bounded polyhedra, which exist in all Euclidean dimensions, and are are closed under intersection, rotation and relative complement? In other words, I am looking for a set ...
ABCD is a tetrahedron (not necessarly a regular one). A Monge's plane is a plane which is perpendicular to an edge and goes through the middle of the opposite edge. I want to prove that the 6 ...