English
The set of indeterminates X for the multivariate polynomial ring in an index set ι forms a transcendence basis over R.
Русский
Набор неопределённых переменных X для многочлена векторной переменной образует базис трансцендентности над R.
LaTeX
$$$ IsTranscendenceBasis R (X (R := R) (\sigma := ι))$$$
Lean4
theorem mvPolynomial [Nontrivial R] : IsTranscendenceBasis R (X (R := R) (σ := ι)) :=
by
refine isTranscendenceBasis_iff_algebraicIndependent_isAlgebraic.2 ⟨algebraicIndependent_X .., ?_⟩
rw [adjoin_range_X]
set A := MvPolynomial ι R
have := Algebra.isIntegral_of_surjective (R := (⊤ : Subalgebra R A)) (B := A) (⟨⟨·, ⟨⟩⟩, rfl⟩)
infer_instance