A surface which is homeomorphic to a finite collection of spheres, each with a finite number of handles, cross-handles, cross-caps, and perforations. A preliminary version of the classification theorem of surfaces states that every surface is ordinary.

# Ordinary Surface

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## References

Francis, G. K. and Weeks, J. R. "Conway's ZIP Proof."*Amer. Math. Monthly*

**106**, 393-399, 1999.

## Referenced on Wolfram|Alpha

Ordinary Surface## Cite this as:

Weisstein, Eric W. "Ordinary Surface."
From *MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/OrdinarySurface.html