Formulas
- Atiyah–Bott fixed-point theorem
- Atiyah–Hirzebruch spectral sequence
- Atiyah–Segal completion theorem
- Atom (measure theory)
- Atoroidal
- Attack Vector: Tactical
- Attractor
- Aubin–Lions lemma
- Interpunct
- Intersection theory
- Interval (mathematics)
- Introduction to the mathematics of general relativity
- Inverse element
- Inverse function
- Inverse limit