English
Under NoZeroDivisors on R and a nontrivial S, any basis b of S over R ensures that the algebra map from R to S is injective.
Русский
При отсутствии нулевых делителей в R и ненулевом S отображение алгебраMap из R в S инъективно для любой базы.
LaTeX
$$$$ \text{algebraMap } R S \text{ injective} $$$$
Lean4
theorem algebraMap_injective {ι : Type*} [NoZeroDivisors R] [Nontrivial S] (b : Basis ι R S) :
Function.Injective (algebraMap R S) :=
have : NoZeroSMulDivisors R S := b.noZeroSMulDivisors
FaithfulSMul.algebraMap_injective R S