birationally
Adverb
Meaning
birationally (not comparable)
(mathematics) In birational terms.
Two varieties are said to be birationally equivalent if there exists a birational map between them.
Examples
Equivalently, they are birationally equivalent if their function fields are isomorphic.
This means that any algebraic variety can be replaced by (more precisely is birationally equivalent to) a similar variety which has no singularities.