English
If for every finite subset t of ι, the finite evaluation x|t is algebraically independent, then x is algebraically independent.
Русский
Если для каждого конечного подмножества t индексов ι семейство x|t алгебраически независимо, то само x алгебраически независимо.
LaTeX
$$$\forall t \subseteq ι,\ t\text{ finite }\Rightarrow \text{AlgebraicIndependent}_R (\lambda i. x i)\big|_{t}$$$
Lean4
theorem algebraicIndependent_of_finite_type (H : ∀ t : Set ι, t.Finite → AlgebraicIndependent R fun i : t ↦ x i) :
AlgebraicIndependent R x :=
(injective_iff_map_eq_zero _).mpr fun p ↦
algebraicIndependent_comp_subtype.1 (H _ p.vars.finite_toSet) _ p.mem_supported_vars