Theorem bj-nnfim1 37613

Description: A consequence of nonfreeness in the antecedent and the consequent of an implication. (Contributed by BJ, 27-Aug-2023.)

Assertion

Ref	Expression
bj-nnfim1	⊢ ((Ⅎ'𝑥𝜑 ∧ Ⅎ'𝑥𝜓) → ((𝜑 → 𝜓) → (∃𝑥𝜑 → ∀𝑥𝜓)))

Proof of Theorem bj-nnfim1

Step	Hyp	Ref	Expression
1		bj-nnfe 37603	. 2 ⊢ (Ⅎ'𝑥𝜑 → (∃𝑥𝜑 → 𝜑))
2		bj-nnfa 37600	. 2 ⊢ (Ⅎ'𝑥𝜓 → (𝜓 → ∀𝑥𝜓))
3		imim12 106	. . 3 ⊢ ((∃𝑥𝜑 → 𝜑) → ((𝜓 → ∀𝑥𝜓) → ((𝜑 → 𝜓) → (∃𝑥𝜑 → ∀𝑥𝜓))))
4	3	imp 412	. 2 ⊢ (((∃𝑥𝜑 → 𝜑) ∧ (𝜓 → ∀𝑥𝜓)) → ((𝜑 → 𝜓) → (∃𝑥𝜑 → ∀𝑥𝜓)))
5	1, 2, 4	syl2an 608	1 ⊢ ((Ⅎ'𝑥𝜑 ∧ Ⅎ'𝑥𝜓) → ((𝜑 → 𝜓) → (∃𝑥𝜑 → ∀𝑥𝜓)))

This proof depends on syntax axioms:   → wi 4   ∧ wa 401  ∀wal 1568  ∃wex 1812  Ⅎ'wnnf 37598

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-bj-nnf 37599

This theorem is used by:  bj-nnfim  37624