Source: wikibot/belyi-s-theorem
= Belyi's theorem
{wiki=Belyi's_theorem}
Belyi's theorem is a result in algebraic geometry concerning the characterization of certain algebraic curves. Specifically, it states that a smooth, projective, and geometrically irreducible algebraic curve defined over a number field can be defined over a finite field (in particular, over the algebraic closure of a finite field) if and only if it can be defined by a Belyi function.