Hilbert's Theorem
Every Modular System has a Modular System Basis consisting of a finite number ofPolynomials. Stated another way, for every order 
there exists a nonsingular curve with the maximumnumber of circuits and the maximum number for any one nest.
References
Coolidge, J. L. A Treatise on Algebraic Plane Curves. New York: Dover, p. 61, 1959.
- Angle of Parallelism
- Angle Trisection
- Angular Acceleration
- Angular Defect
- Angular Distance
- Angular Velocity
- Anharmonic Ratio
- Anisohedral Tiling
- Annihilator
- Annulus
- Annulus Conjecture
- Annulus Theorem
- Anomalous Cancellation
- Anomalous Number
- Anonymous
- Anosov Automorphism
- Anosov Diffeomorphism
- Anosov Flow
- Anosov Map
- ANOVA
- Anthropomorphic Polygon
- Anthyphairetic Ratio
- Antiautomorphism
- Anticevian Triangle
- Antichain