English
If p and q are irreducible and u, v are units with u p^m = v q^n, then u = v when m = n and p, q are associates appropriately.
Русский
Если p и q ирредуцируемы и u, v — единицы с u p^m = v q^n, то при равенстве степеней и соответствующей эквиваленции ирредуцируемых верна t.
LaTeX
$$$m = n \implies u = v$$$
Lean4
theorem unit_mul_pow_congr_unit {ϖ : R} (hirr : Irreducible ϖ) (u v : Rˣ) (m n : ℕ) (h : ↑u * ϖ ^ m = v * ϖ ^ n) :
u = v := by
obtain rfl : m = n := unit_mul_pow_congr_pow hirr hirr u v m n h
rw [← sub_eq_zero] at h
rw [← sub_mul, mul_eq_zero] at h
rcases h with h | h
· rw [sub_eq_zero] at h
exact mod_cast h
· apply (hirr.ne_zero (pow_eq_zero h)).elim