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 |