Metamath Proof Explorer


Theorem nlim2NEW

Description: 2 is not a limit ordinal. (Contributed by BTernaryTau, 1-Dec-2024) (Proof shortened by RP, 13-Dec-2024)

Ref Expression
Assertion nlim2NEW ¬ Lim 2o

Proof

Step Hyp Ref Expression
1 1on ⊢ 1o ∈ On
2 nlimsuc ⊢ ( 1o ∈ On → ¬ Lim suc 1o )
3 df-2o ⊢ 2o = suc 1o
4 limeq ⊢ ( 2o = suc 1o → ( Lim 2o ↔ Lim suc 1o ) )
5 3 4 ax-mp ⊢ ( Lim 2o ↔ Lim suc 1o )
6 2 5 sylnibr ⊢ ( 1o ∈ On → ¬ Lim 2o )
7 1 6 ax-mp ⊢ ¬ Lim 2o