∀n:ℕ. ∀x:ℕ+. 0 < x^n
{ InductionOnNat }
.....basecase.....
1. n : ℤ
⊢ ∀x:ℕ+. 0 < x^0
.....upcase.....
2. 0 < n
3. ∀x:ℕ+. 0 < x^n - 1
⊢ ∀x:ℕ+. 0 < x^n