noun which may take the genitive case particle 'no'
birational
Technical term in algebraic geometry describing a relation between varieties that are isomorphic outside lower-dimensional subsets.
Birationally equivalent algebraic varieties have isomorphic function fields.
This map is a birational map.
Compound of 双 (sō, 'pair, both') and 有理 (yūri, 'rational'), calque of English 'birational'.