Metamath Proof Explorer


Theorem 1sdom2

Description: Ordinal 1 is strictly dominated by ordinal 2. (Contributed by NM, 4-Apr-2007)

Ref Expression
Assertion 1sdom2 1o ≺ 2o

Proof

Step Hyp Ref Expression
1 1onn 1o ∈ ω
2 php4 ( 1o ∈ ω → 1o ≺ suc 1o )
3 1 2 ax-mp 1o ≺ suc 1o
4 df-2o 2o = suc 1o
5 3 4 breqtrri 1o ≺ 2o