Description: The abstraction of a wff with existential uniqueness exists. (Contributed by NM, 25-Nov-1994)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | euabex | ⊢ ( ∃! 𝑥 𝜑 → { 𝑥 ∣ 𝜑 } ∈ V ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eumo | ⊢ ( ∃! 𝑥 𝜑 → ∃* 𝑥 𝜑 ) | |
| 2 | moabex | ⊢ ( ∃* 𝑥 𝜑 → { 𝑥 ∣ 𝜑 } ∈ V ) | |
| 3 | 1 2 | syl | ⊢ ( ∃! 𝑥 𝜑 → { 𝑥 ∣ 𝜑 } ∈ V ) |