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Description: Proof of pwuninel under the assumption that the union of the given class is a set, avoiding ax-pr and ax-un . (Contributed by Stefan O'Rear, 22-Feb-2015)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pwuninel2 | ⊢ ( ∪ 𝐴 ∈ 𝑉 → ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pwnss | ⊢ ( ∪ 𝐴 ∈ 𝑉 → ¬ 𝒫 ∪ 𝐴 ⊆ ∪ 𝐴 ) | |
| 2 | elssuni | ⊢ ( 𝒫 ∪ 𝐴 ∈ 𝐴 → 𝒫 ∪ 𝐴 ⊆ ∪ 𝐴 ) | |
| 3 | 1 2 | nsyl | ⊢ ( ∪ 𝐴 ∈ 𝑉 → ¬ 𝒫 ∪ 𝐴 ∈ 𝐴 ) |