Metamath Proof Explorer


Theorem pellfundne1

Description: The fundamental Pell solution is never 1. (Contributed by Stefan O'Rear, 19-Sep-2014)

Ref Expression
Assertion pellfundne1 ⊢ D ∈ ℕ ∖ ◻ ℕ → PellFund ⁡ D ≠ 1

Proof

Step Hyp Ref Expression
1 1red ⊢ D ∈ ℕ ∖ ◻ ℕ → 1 ∈ ℝ
2 pellfundgt1 ⊢ D ∈ ℕ ∖ ◻ ℕ → 1 < PellFund ⁡ D
3 1 2 gtned ⊢ D ∈ ℕ ∖ ◻ ℕ → PellFund ⁡ D ≠ 1