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 ) |