Theorem moor 2554

Description: "At most one" is still the case when a disjunct is removed. (Contributed by NM, 5-Apr-2004.)

Assertion

Ref	Expression
moor	⊢ (∃*𝑥(𝜑 ∨ 𝜓) → ∃*𝑥𝜑)

Proof of Theorem moor

Step	Hyp	Ref	Expression
1		orc 867	. 2 ⊢ (𝜑 → (𝜑 ∨ 𝜓))
2	1	moimi 2545	1 ⊢ (∃*𝑥(𝜑 ∨ 𝜓) → ∃*𝑥𝜑)

Syntax hints:   → wi 4   ∨ wo 847  ∃*wmo 2538

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809

This theorem depends on definitions:  df-bi 207  df-or 848  df-ex 1780  df-mo 2540

This theorem is referenced by:  mooran2  2556