previous up next
Go backward to Constructor function
Go up to Top
Go forward to Rational Arithmetic
RISC-Linz logo

Numerator and Denominator

Let r in Q and take x and y such that r=<x, y>. We call x the numerator of r and y its denominator:

numerator(r) := such x: exists y: r in Q /\  r = <x, y>;
denominator(r) := such y: exists x: r in Q /\  r = <x, y>.

Numerator and denominator are uniquely defined.

Author: Wolfgang Schreiner
Last Modification: November 16, 1999

previous up next