Poincaré Formula
The Polyhedral Formula generalized to a surface of Genus 
.
where
is the number of Vertices, 
is the number of Edges,
is the number of faces, and
is called the Euler Characteristic.See also Euler Characteristic, Genus (Surface), Polyhedral Formula
References
Eppstein, D. ``Fourteen Proofs of Euler's Formula: 
.'' http://www.ics.uci.edu/~eppstein/junkyard/euler/.
- Conic Section
- Conic Section Tangent
- Conjecture
- Conjugacy Class
- Conjugate Element
- Conjugate Gradient Method
- Conjugate Points
- Conjugate Subgroup
- Conjugation
- Conjunction
- Connected Graph
- Connected Set
- Connected Space
- Connected Sum
- Connected Sum Decomposition
- Connection
- Connection Coefficient
- Connectivity
- Connes Function
- Conocuneus of Wallis
- Conoid
- Consecutive Number Sequences
- Conservation of Number Principle
- Conservative Field
- Consistency