Zulip Chat Archive

Stream: Is there code for X?

Topic: pow left is injective for reals


Snir Broshi (Oct 07 2025 at 22:01):

theorem foo (n : ) (hn : n  0) (x y : ) (hx : 0  x) (hy : 0  y) :
    x ^ n = y ^ n  x = y := by
  sorry

theorem bar (r : ) (hr : 0 < r) (x y : ) (hx : 0  x) (hy : 0  y) :
    x ^ r = y ^ r  x = y := by
  sorry

Do these exist, or does anyone have counterexamples?
I found a similar theorem for HPow.hPow ℕ ℕ ℕ: docs#Nat.pow_left_injective

Damiano Testa (Oct 07 2025 at 22:06):

Maybe docs#Real.rpow_left_inj ?

Damiano Testa (Oct 07 2025 at 22:07):

simp_all proves the first.

Damiano Testa (Oct 07 2025 at 22:10):

In fact, pow_left_inj₀ hx hy hn proves the first and Real.rpow_left_inj hx hy hr.ne' proves the second.


Last updated: Dec 20 2025 at 21:32 UTC