Fundamental Group
The fundamental group of a Connected Set 
is the Quotient Group of the Group of all paths with initialand final points at a given point 
and the Subgroup of all paths Homotopic to thedegenerate path consisting of the point .
The fundamental group of the Circle is the Infinite Cyclic Group. Two fundamental groups having differentpoints are Isomorphic. If the fundamental group consists only of the identity element, thenthe set is Simply Connected.
- Nonconformal Mapping
- Nonconstructive Proof
- Noncototient
- Noncylindrical Ruled Surface
- Nondecreasing Function
- Nondividing Set
- Nonessential Singularity
- Non-Euclidean Geometry
- Nonillion
- Nonincreasing Function
- Nonlinear Least Squares Fitting
- Nonnegative
- Nonnegative Integer
- Nonnegative Partial Sum
- Nonorientable Surface
- Nonpositive
- Nonsquarefree
- Nonstandard Analysis
- Nontotient
- Nonwandering
- Nonzero
- Nordstrand's Weird Surface
- Norm
- Normal
- Normal (Algebraically)