Similar to シュトルツ＝チェザロの定理

Atiyah–Singer index theorem

Sieve of Atkin

Apéry's constant

Apéry's theorem

Abel–Plana formula

Apollonius point

Apollonian gasket

Archimedes's cattle problem

Archimedean property

Twin circles

Algorithm

Artin L-function

Artin–Hasse exponential

Wedderburn–Artin theorem

Artinian module

Artinian ring

Euler numbers

Cousin's theorem

Krein–Milman theorem

Krylov–Bogolyubov theorem

Kempner function

Root test

Sicherman dice

Schwartz space

Cesàro mean

Cesàro summation