Description: The power set of the empty set (the ordinal 1) is a set. See also p0exALT . (Contributed by NM, 23-Dec-1993)
Ref | Expression | ||
---|---|---|---|
Assertion | p0ex | ⊢ { ∅ } ∈ V |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pw0 | ⊢ 𝒫 ∅ = { ∅ } | |
2 | 0ex | ⊢ ∅ ∈ V | |
3 | 2 | pwex | ⊢ 𝒫 ∅ ∈ V |
4 | 1 3 | eqeltrri | ⊢ { ∅ } ∈ V |