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Metamath Proof Explorer

Theorem bnj105

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Assertion bnj105 1o ∈ V

Proof

Step Hyp Ref Expression
1 df1o2 ⊢ 1o = { ∅ }
2 p0ex ⊢ { ∅ } ∈ V
3 1 2 eqeltri ⊢ 1o ∈ V