English
If IsPrimitiveRoot(f ζ, k) and f is injective, then IsPrimitiveRoot ζ k.
Русский
Если IsPrimitiveRoot(f ζ, k) и f инъективен, тогда IsPrimitiveRoot ζ k.
LaTeX
$$$$ IsPrimitiveRoot( f\zeta, k) \land \text{Injective}(f) \Rightarrow IsPrimitiveRoot(\zeta, k). $$$$
Lean4
theorem of_map_of_injective [MonoidHomClass F M N] (h : IsPrimitiveRoot (f ζ) k) (hf : Injective f) :
IsPrimitiveRoot ζ k where
pow_eq_one := by apply_fun f; rw [map_pow, map_one, h.pow_eq_one]
dvd_of_pow_eq_one := by
rw [h.eq_orderOf]
intro l hl
apply_fun f at hl
rw [map_pow, map_one] at hl
exact orderOf_dvd_of_pow_eq_one hl