Affine Geometry
A Geometry in which properties are preserved by Parallel Projection from one Plane to another. In an affine geometry, the third and fourth of Euclid's Postulates become meaningless. This type of Geometrywas first studied by Euler. 
References
Birkhoff, G. and Mac Lane, S. ``Affine Geometry.'' §9.13 in A Survey of Modern Algebra, 3rd ed. New York: Macmillan, pp. 268-275, 1965.
- Infinary Perfect Number
- Infinite
- Infinite Product
- Infinite Series
- Infinite Set
- Infinitesimal
- Infinitesimal Analysis
- Infinitesimal Matrix Change
- Infinitesimal Rotation
- Infinitive Sequence
- Infinitude of Primes
- Infinity
- Inflection Point
- Information Dimension
- Information Entropy
- Information Theory
- Initial Value Problem
- Injection
- Injective
- Injective Patch
- Inner Automorphism Group
- Inner Product
- Inner Product Space
- Inradius
- Inscribed