Assertion: polyhedron's vertex | /r/HasProperty | incident
Facets:
Source sentences:
text: For example a cross-quadrilateral (a butterfly or hourglass shape) has four vertices each connected to, i.e. incident with, two sides.
text: Mention the additional restrictions necessary to ensure that the abstract polyhedron is a manifold (namely that each face is incident to a simple cycle of vertices and edges, and each vertex is incident to a simple cycle of faces and edges) and state that with these restrictions abstract polyhedra carry exactly the same information as topological polyhedra.