Prime Power Conjecture
An Abelian planar Difference Set of order 
exists only for a Prime Power. Gordon (1994) has verifiedit to be true for 
.
References
Gordon, D. M. ``The Prime Power Conjecture is True for .'' Electronic J. Combinatorics 1, R6 1-7, 1994.http://www.combinatorics.org/Volume_1/volume1.html#R6.
- Layer
- Leading Digit Phenomenon
- Leading Order Analysis
- Leaf (Foliation)
- Leaf (Tree)
- Leakage
- Least Bound
- Least Common Multiple
- Least Deficient Number
- Least Period
- Least Prime Factor
- Least Squares Fitting
- Least Squares Fitting--Exponential
- Least Squares Fitting--Logarithmic
- Least Squares Fitting--Power Law
- Least Upper Bound
- Lebesgue Constants (Fourier Series)
- Lebesgue Constants (Lagrange Interpolation)
- Lebesgue Covering Dimension
- Lebesgue Dimension
- Lebesgue Integrable
- Lebesgue Integral
- Lebesgue Measurability Problem
- Lebesgue Measure
- Lebesgue Minimal Problem