English
An element x is transcendental over R iff the kernel of the ring homomorphism aeval x is the zero ideal.
Русский
Элемент x трансцендентен над R тогда и только тогда, когда ядро гомоморфизма aeval x равно нулевому идеалу.
LaTeX
$$$ Transcendental R x \iff \ RingHom.ker (aeval (R := R) x) = \bot $$$
Lean4
/-- An element `x` is transcendental over `R` if and only if the kernel of the ring homomorphism
`Polynomial.aeval x` is the zero ideal. This is similar to `algebraicIndependent_iff_ker_eq_bot`. -/
theorem transcendental_iff_ker_eq_bot {x : A} : Transcendental R x ↔ RingHom.ker (aeval (R := R) x) = ⊥ := by
rw [transcendental_iff_injective, RingHom.injective_iff_ker_eq_bot]