Ordinary Line
Given an arrangement of 
points, a Line containing just two of them is called an ordinary line.Moser (1958) proved that at least 
lines must be ordinary (Guy 1989, p. 903).
References
Guy, R. K. ``Unsolved Problems Come of Age.'' Amer. Math. Monthly 96, 903-909, 1989.
- Parity
- Parity Constant
- Parking Constant
- Parodi's Theorem
- Parry Circle
- Parry Point
- Parseval's Integral
- Parseval's Relation
- Parseval's Theorem
- Partial Derivative
- Partial Differential Equation
- Partial Fraction Decomposition
- Partial Latin Square
- Partially Ordered Set
- Partial Order
- Partial Quotient
- Particularly Well-Behaved Functions
- Partisan Game
- Partition
- Partition Function P
- Partition Function Q
- Part Metric
- Party Problem
- Parzen Apodization Function
- Pascal Distribution