Euler characteristic of a polyhedron

The Euler characteristic gives an integer that counts vertices minus edges plus faces of a polyhedron, and for a convex polyhedron it equals 2. More generally it is an alternating sum of Betti numbers or cell counts, a topological invariant that helps distinguish and classify surfaces and other spaces.

\chi=V-E+F

What the symbols mean

Euler characteristic (dimensionless integer)
number of vertices
number of edges
number of faces

About this formula

  • FieldMathematics
  • TopicTopology
  • LevelUniversity
  • Also calledEuler polyhedron formula, V minus E plus F, vertices edges faces formula, Euler characteristic, Euler-Poincaré characteristic, Euler's polyhedron theorem
  • SourceWikidata Q852973

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