Theorem axextprim 36213

Description: ax-ext 2738 without distinct variable conditions or defined symbols. (Contributed by Scott Fenton, 13-Oct-2010.)

Assertion

Ref	Expression
axextprim	⊢ ¬ ∀𝑥 ¬ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧))

Proof of Theorem axextprim

Step	Hyp	Ref	Expression
1		axextnd 10594	. 2 ⊢ ∃𝑥((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) → 𝑦 = 𝑧)
2		dfbi2 480	. . . . . 6 ⊢ ((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) ↔ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) ∧ (𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦)))
3	2	imbi1i 352	. . . . 5 ⊢ (((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) → 𝑦 = 𝑧) ↔ (((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) ∧ (𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦)) → 𝑦 = 𝑧))
4		impexp 456	. . . . 5 ⊢ ((((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) ∧ (𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦)) → 𝑦 = 𝑧) ↔ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)))
5	3, 4	bitri 278	. . . 4 ⊢ (((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) → 𝑦 = 𝑧) ↔ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)))
6	5	exbii 1881	. . 3 ⊢ (∃𝑥((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) → 𝑦 = 𝑧) ↔ ∃𝑥((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)))
7		df-ex 1813	. . 3 ⊢ (∃𝑥((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)) ↔ ¬ ∀𝑥 ¬ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)))
8	6, 7	bitri 278	. 2 ⊢ (∃𝑥((𝑥 ∈ 𝑦 ↔ 𝑥 ∈ 𝑧) → 𝑦 = 𝑧) ↔ ¬ ∀𝑥 ¬ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧)))
9	1, 8	mpbi 233	1 ⊢ ¬ ∀𝑥 ¬ ((𝑥 ∈ 𝑦 → 𝑥 ∈ 𝑧) → ((𝑥 ∈ 𝑧 → 𝑥 ∈ 𝑦) → 𝑦 = 𝑧))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 401  ∀wal 1568  ∃wex 1812

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2148  ax-9 2156  ax-10 2179  ax-11 2195  ax-12 2216  ax-13 2407  ax-ext 2738

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-tru 1573  df-ex 1813  df-nf 1817  df-clel 2841  df-nfc 2915

This theorem is used by: (None)