Assertion: polyhedron's vertex | /r/HasProperty | common
Facets:
value: to only 3 faces
type: OTHER
Source sentences:
text: Using Euler's polyhedron formula, V - E + F = 2, and assuming that all vertices are common to only 3 faces, it's not hard to work out that if there's 1 heptagon, then there has to be 13 pentagons, while hexagons are freebies.