English
For all p and all d, the coefficient of d in the p-th homogeneous component of f equals the coefficient of d in f if deg(d) = p, and is 0 otherwise.
Русский
Для всех p и d коэффициент d в p-й однородной компоненте f равен коэффициенту d в f, если deg(d) = p, иначе равен 0.
LaTeX
$$coeff_d(homogeneousComponent(p) f) = if degree(d) = p then coeff_d f else 0$$
Lean4
theorem coeff_homogeneousComponent (p : ℕ) (d : σ →₀ ℕ) (f : MvPowerSeries σ R) :
coeff d (homogeneousComponent p f) = if degree d = p then coeff d f else 0 :=
by
rw [degree_eq_weight_one]
exact coeff_weightedHomogeneousComponent 1 p d f