Rodrigues's Curvature Formula
where
is the unit Normal Vector and 
is one of the two Principal Curvatures.See also Normal Vector, Principal Curvatures- Prouhet's Problem
- Prussian Hat
- Prüfer Ring
- p-Series
- Pseudoanalytic Function
- Pseudocrosscap
- Pseudocylindrical Projection
- Pseudogroup
- Pseudolemniscate Case
- Pseudoperfect Number
- Pseudoprime
- Pseudorandom Number
- Pseudorhombicuboctahedron
- Pseudoscalar
- Pseudosmarandache Function
- Pseudosphere
- Pseudosquare
- Pseudotensor
- Pseudovector
- Psi Function
- p-Signature
- PSLQ Algorithm
- PSOS Algorithm
- P-Symbol
- Ptolemy Inequality