Unital
A Block Design of the form (
, 
, 1).
References
Dinitz, J. H. and Stinson, D. R. ``A Brief Introduction to Design Theory.'' Ch. 1 in Contemporary Design Theory: A Collection of Surveys (Ed. J. H. Dinitz and D. R. Stinson). New York: Wiley, pp. 1-12, 1992.
- Artistic Series
- ASA Theorem
- Aschbacher's Component Theorem
- A-Sequence
- Associative
- Associative Algebra
- Associative Magic Square
- ASS Theorem
- Astroid
- Astroidal Ellipsoid
- Astroid Evolute
- Astroid Involute
- Astroid Pedal Curve
- Astroid Radial Curve
- Asymptosy
- Asymptote
- Asymptotic
- Asymptotic Curve
- Asymptotic Direction
- Asymptotic Notation
- Asymptotic Series
- Atiyah-Singer Index Theorem
- Atkin-Goldwasser-Kilian-Morain Certificate
- Atomic Statement
- Attraction Basin