English
Repeatedly, coefficient after mapRange equals applying g to the coefficient: coeff m (mapRange g hg φ) = g (coeff m φ).
Русский
Снова коэффициент после mapRange равен применению g к коэффициенту: coeff m (mapRange g hg φ) = g (coeff m φ).
LaTeX
$$$\mathrm{coeff}\;m (\mathrm{mapRange}\ g\ hg\ \varphi) = g(\mathrm{coeff}\;m\ \varphi)$$$
Lean4
@[simp]
theorem coeff_C [DecidableEq σ] (m) (a) : coeff m (C a : MvPolynomial σ R) = if 0 = m then a else 0 :=
Finsupp.single_apply