Description: "At most one" is still the case when a disjunct is removed. (Contributed by NM, 5-Apr-2004)
Ref | Expression | ||
---|---|---|---|
Assertion | moor | ⊢ ( ∃* 𝑥 ( 𝜑 ∨ 𝜓 ) → ∃* 𝑥 𝜑 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | orc | ⊢ ( 𝜑 → ( 𝜑 ∨ 𝜓 ) ) | |
2 | 1 | moimi | ⊢ ( ∃* 𝑥 ( 𝜑 ∨ 𝜓 ) → ∃* 𝑥 𝜑 ) |