English
Rescale by zero equals the composition of the constant-coefficient series with the constant term operator.
Русский
Масштабирование нулём равно композиции константного ряда с операцией извлечения константного коэффициента.
LaTeX
$$$\mathrm{rescale}\, 0 = (C \circ \operatorname{constantCoeff})$$$
Lean4
@[simp]
theorem rescale_zero : rescale 0 = (C (R := R)).comp constantCoeff :=
by
ext x n
simp only [Function.comp_apply, RingHom.coe_comp, rescale, RingHom.coe_mk, coeff_C]
split_ifs with h <;> simp [h]