English
If f is injective, then the support of rename f p is the image of the support of p under mapDomain f.
Русский
Если f инъективно, то поддержка rename f p равна образу поддержки p под mapDomain f.
LaTeX
$$$ \mathrm{support}(\mathrm{rename}\ f\ p) = \mathrm{Finset.image}(\mathrm{Finsupp.mapDomain} f)\, p.\mathrm{support} $$$
Lean4
theorem support_rename_of_injective {p : MvPolynomial σ R} {f : σ → τ} [DecidableEq τ] (h : Function.Injective f) :
(rename f p).support = Finset.image (Finsupp.mapDomain f) p.support :=
by
rw [rename_eq]
exact Finsupp.mapDomain_support_of_injective (Finsupp.mapDomain_injective h) _