English
For a group action of G on R, IsCoprime(x • y, z) is equivalent to IsCoprime(y, z); the map uses the action to move the factor x to the scalar.
Русский
Для групового действия G на R, IsCoprime(x • y, z) эквивалентно IsCoprime(y, z).
LaTeX
$$$\operatorname{IsCoprime}(x \cdot y, z) \iff \operatorname{IsCoprime}(y, z)$$$
Lean4
theorem isCoprime_group_smul_left : IsCoprime (x • y) z ↔ IsCoprime y z :=
⟨fun ⟨a, b, h⟩ => ⟨x • a, b, by rwa [smul_mul_assoc, ← mul_smul_comm]⟩, fun ⟨a, b, h⟩ =>
⟨x⁻¹ • a, b, by rwa [smul_mul_smul_comm, inv_mul_cancel, one_smul]⟩⟩