English
The numerator of a RatFunc is defined as the first component of the pair numDenom(x).
Русский
Числитель рациональной функции определён как первая координата пары numDenom(x).
LaTeX
$$$\operatorname{num}(x) = \operatorname{fst}(\operatorname{numDenom}(x))$$$
Lean4
/-- `RatFunc.num` is the numerator of a rational function,
normalized such that the denominator is monic. -/
def num (x : RatFunc K) : K[X] :=
x.numDenom.1