a function (= a quantity whose value depends on other values) that can be written as a fraction in which one polynomial (= a number or mathematical symbol, or the result of adding or subtracting two or more numbers) is divided by another polynomial

First we consider the problems whose solutions are rational functions of the parameters. 首先我们考虑那些解是参数的有理函数的问题。

This shows that F is a non-constant rational function.