In abstract
geometry, a
hemi-cube is an
abstract regular polyhedron, containing half the faces of a
cube. It exists on a
hemisphere as a
projective plane where opposite points along the boundary are connected.
It has 3 square faces, 6 edges, and 4 vertices.
From the point of view of graph theory this is an embedding of (the complete graph with 4 vertices) on a projective plane.
See also