Metamath Proof Explorer


Theorem bnj1071

Description: Technical lemma for bnj69 . This lemma may no longer be used or have become an indirect lemma of the theorem in question (i.e. a lemma of a lemma... of the theorem). (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypothesis bnj1071.7 ⊢ D = ω ∖ ∅
Assertion bnj1071 ⊢ n ∈ D → E Fr n

Proof

Step Hyp Ref Expression
1 bnj1071.7 ⊢ D = ω ∖ ∅
2 1 bnj923 ⊢ n ∈ D → n ∈ ω
3 nnord ⊢ n ∈ ω → Ord ⁡ n
4 ordfr ⊢ Ord ⁡ n → E Fr n
5 2 3 4 3syl ⊢ n ∈ D → E Fr n