Metamath Proof Explorer


Theorem eluz2b3

Description: Two ways to say "an integer greater than or equal to 2." (Contributed by Paul Chapman, 23-Nov-2012)

Ref Expression
Assertion eluz2b3 ( 𝑁 ∈ ( ℤ ‘ 2 ) ↔ ( 𝑁 ∈ ℕ ∧ 𝑁 ≠ 1 ) )

Proof

Step Hyp Ref Expression
1 eluz2b2 ( 𝑁 ∈ ( ℤ ‘ 2 ) ↔ ( 𝑁 ∈ ℕ ∧ 1 < 𝑁 ) )
2 nngt1ne1 ( 𝑁 ∈ ℕ → ( 1 < 𝑁𝑁 ≠ 1 ) )
3 2 pm5.32i ( ( 𝑁 ∈ ℕ ∧ 1 < 𝑁 ) ↔ ( 𝑁 ∈ ℕ ∧ 𝑁 ≠ 1 ) )
4 1 3 bitri ( 𝑁 ∈ ( ℤ ‘ 2 ) ↔ ( 𝑁 ∈ ℕ ∧ 𝑁 ≠ 1 ) )