Similar to マルファッティの円

Apollonius point

Twin circles

Yff center of congruence

Schiffler point

Spieker circle

Circumgon

Encyclopedia of Triangle Centers

Circumcircle

Incircle and excircles

Orthocentroidal circle

Taylor circle

Annales de Gergonne

P-adic Teichmüller theory

RSA (cryptosystem)

Witch of Agnesi

Abelian group

Category of abelian groups

Abelian category

Abelian variety

Abel's theorem

Abel equation

Abel–Jacobi map

Abel–Ruffini theorem

Eisenstein series

Eisenstein integer

Iverson bracket