Similar to マッセルマンの定理

Leon Battista Alberti

Almagest

Alexander horned sphere

Alexander's theorem

Menelaus of Alexandria

Pavel Alexandrov

Alexandroff extension

Aleph number

Allen–Cahn equation

Nachman Aronszajn

Aronszajn tree

Polar circle (geometry)

Thébault's theorem

Reuschle's theorem

Incenter–excenter lemma

Japanese theorem for cyclic polygons

Harcourt's theorem

Lune of Hippocrates

Van Schooten's theorem

Fuhrmann circle

Pompeiu's theorem

Miquel's theorem

Lester's theorem

Six circles theorem