Stokes Phenomenon
The asymptotic expansion of the Airy Function 
(and other similar functions) has adifferent form in different sectors of the Complex Plane.
References
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 609-611, 1953.
- Pluperfect Number
- Plurisubharmonic Function
- Plus
- Plus or Minus
- Plus Perfect Number
- Plus Sign
- Plutarch Numbers
- Plücker Characteristics
- Plücker Relations
- Plücker's Conoid
- Plücker's Equations
- Pochhammer Symbol
- Pocklington-Lehmer Test
- Pocklington's Criterion
- Pocklington's Theorem
- Poggendorff Illusion
- Pohlke's Theorem
- Poincaré-Birkhoff Fixed Point Theorem
- Poincaré Conjecture
- Poincaré Duality
- Poincaré Formula
- Poincaré-Fuchs-Klein Automorphic Function
- Poincaré Group
- Poincaré-Hopf Index Theorem
- Poincaré Hyperbolic Disk