Simply Connected
A Connected Domain is said to be simply connected (also called 1-connected) if any simpleclosed curve can be shrunk to a point continuously in the set. If the domain is Connected but notsimply, it is said to be Multiply Connected.
A Space 
is simply connected if it is 0-connected and if every Map from the 1-Sphere to extendscontinuously to a Map from the 2-Disk. In other words, every loop in the Space is contractible.
- Lefshetz Trace Formula
- Leg
- Legendre Addition Theorem
- Legendre Differential Equation
- Legendre Duplication Formula
- Legendre Function of the First Kind
- Legendre Function of the Second Kind
- Legendre-Gauss Quadrature
- Legendre-Jacobi Elliptic Integral
- Legendre Polynomial
- Legendre Polynomial of the Second Kind
- Legendre Quadrature
- Legendre Relation
- Legendre's Chi-Function
- Legendre's Constant
- Legendre Series
- Legendre's Factorization Method
- Legendre's Formula
- Legendre's Quadratic Reciprocity Law
- Legendre Sum
- Legendre Symbol
- Legendre Transformation
- Lehmer Method
- Lehmer Number
- Lehmer-Schur Method