Assertion: polyhedron's surface | /r/HasAspect | euler characteristic
Facets:
value: like the torus
type: OTHER
Source sentences:
text: Projective polyhedra all have Euler characteristic 1, like the real projective plane, while the surfaces of toroidal polyhedra all have Euler characteristic 0, like the torus.
text: The surfaces of nonconvex polyhedra can have various Euler characteristics: