Theorem alseu2d 50664

Description: Deduction rule: Given "all some one" applied to a top-level inference, you can extract the "exactly one" part. (Contributed by David A. Wheeler, 21-Jul-2026.)

Hypothesis

Ref	Expression
alseu2d.1	⊢ (𝜑 → ∀∃!𝑥(𝜓 → 𝜒))

Assertion

Ref	Expression
alseu2d	⊢ (𝜑 → ∃!𝑥𝜓)

Proof of Theorem alseu2d

Step	Hyp	Ref	Expression
1		alseu2d.1	. . 3 ⊢ (𝜑 → ∀∃!𝑥(𝜓 → 𝜒))
2		df-alseu 50656	. . 3 ⊢ (∀∃!𝑥(𝜓 → 𝜒) ↔ (∀𝑥(𝜓 → 𝜒) ∧ ∃!𝑥𝜓))
3	1, 2	sylib 221	. 2 ⊢ (𝜑 → (∀𝑥(𝜓 → 𝜒) ∧ ∃!𝑥𝜓))
4	3	simprd 501	1 ⊢ (𝜑 → ∃!𝑥𝜓)

This proof depends on syntax axioms:   → wi 4   ∧ wa 401  ∀wal 1568  ∃!weu 2598  ∀∃!walseu 50654

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 210  df-an 402  df-alseu 50656

This theorem is used by: (None)