In the mathematical field of differential geometry, more precisely, the theory of surfaces in Euclidean space, the **Bonnet theorem** states that the first and second fundamental forms determine a surface in **R**3 uniquely up to a rigid motion. It was proven by Pierre Ossian Bonnet in about 1860.

This is not to be confused with the Bonnetâ€“Myers theorem or Gaussâ€“Bonnet theorem.

### Famous quotes containing the words theorem and/or bonnet:

“To insure the adoration of a *theorem* for any length of time, faith is not enough, a police force is needed as well.”

—Albert Camus (1913–1960)

“Had I represented twenty thousand voters in Michigan, that political editor would not have known nor cared whether I was the oldest or the youngest daughter of Methuselah, or whether my *bonnet* came from the Ark or from Worth’s.”

—Susan B. Anthony (1820–1906)