English
If hf is a LeftInverse between f:σ→τ and g:τ→σ, then rename f has a left inverse rename g on polynomials.
Русский
Если hf является левым обратным к f:σ→τ и g:τ→σ, то rename f имеет левый обратный на полиномах, заданный rename g.
LaTeX
$$$\\text{LeftInverse}(\\text{rename}_f, \\text{rename}_g) \\quad\\text{whenever } hf: f \\circ g = \\mathrm{id}. $$$
Lean4
theorem rename_leftInverse {f : σ → τ} {g : τ → σ} (hf : Function.LeftInverse f g) :
Function.LeftInverse (rename f : MvPolynomial σ R → MvPolynomial τ R) (rename g) :=
by
intro x
simp [hf.comp_eq_id]