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Theorem ax12inda 36263
 Description: Induction step for constructing a substitution instance of ax-c15 36204 without using ax-c15 36204. Quantification case. (When 𝑧 and 𝑦 are distinct, ax12inda2 36262 may be used instead to avoid the dummy variable 𝑤 in the proof.) (Contributed by NM, 24-Jan-2007.) (Proof modification is discouraged.) (New usage is discouraged.)
Hypothesis
Ref Expression
ax12inda.1 (¬ ∀𝑥 𝑥 = 𝑤 → (𝑥 = 𝑤 → (𝜑 → ∀𝑥(𝑥 = 𝑤𝜑))))
Assertion
Ref Expression
ax12inda (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))
Distinct variable groups:   𝜑,𝑤   𝑥,𝑤   𝑦,𝑤   𝑧,𝑤
Allowed substitution hints:   𝜑(𝑥,𝑦,𝑧)

Proof of Theorem ax12inda
StepHypRef Expression
1 ax6ev 1972 . . 3 𝑤 𝑤 = 𝑦
2 ax12inda.1 . . . . . . 7 (¬ ∀𝑥 𝑥 = 𝑤 → (𝑥 = 𝑤 → (𝜑 → ∀𝑥(𝑥 = 𝑤𝜑))))
32ax12inda2 36262 . . . . . 6 (¬ ∀𝑥 𝑥 = 𝑤 → (𝑥 = 𝑤 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑))))
4 dveeq2-o 36248 . . . . . . . . 9 (¬ ∀𝑥 𝑥 = 𝑦 → (𝑤 = 𝑦 → ∀𝑥 𝑤 = 𝑦))
54imp 410 . . . . . . . 8 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → ∀𝑥 𝑤 = 𝑦)
6 hba1-o 36212 . . . . . . . . . 10 (∀𝑥 𝑤 = 𝑦 → ∀𝑥𝑥 𝑤 = 𝑦)
7 equequ2 2033 . . . . . . . . . . 11 (𝑤 = 𝑦 → (𝑥 = 𝑤𝑥 = 𝑦))
87sps-o 36223 . . . . . . . . . 10 (∀𝑥 𝑤 = 𝑦 → (𝑥 = 𝑤𝑥 = 𝑦))
96, 8albidh 1867 . . . . . . . . 9 (∀𝑥 𝑤 = 𝑦 → (∀𝑥 𝑥 = 𝑤 ↔ ∀𝑥 𝑥 = 𝑦))
109notbid 321 . . . . . . . 8 (∀𝑥 𝑤 = 𝑦 → (¬ ∀𝑥 𝑥 = 𝑤 ↔ ¬ ∀𝑥 𝑥 = 𝑦))
115, 10syl 17 . . . . . . 7 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → (¬ ∀𝑥 𝑥 = 𝑤 ↔ ¬ ∀𝑥 𝑥 = 𝑦))
127adantl 485 . . . . . . . 8 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → (𝑥 = 𝑤𝑥 = 𝑦))
138imbi1d 345 . . . . . . . . . . 11 (∀𝑥 𝑤 = 𝑦 → ((𝑥 = 𝑤 → ∀𝑧𝜑) ↔ (𝑥 = 𝑦 → ∀𝑧𝜑)))
146, 13albidh 1867 . . . . . . . . . 10 (∀𝑥 𝑤 = 𝑦 → (∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑) ↔ ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑)))
155, 14syl 17 . . . . . . . . 9 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → (∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑) ↔ ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑)))
1615imbi2d 344 . . . . . . . 8 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → ((∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑)) ↔ (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))
1712, 16imbi12d 348 . . . . . . 7 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → ((𝑥 = 𝑤 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑))) ↔ (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑)))))
1811, 17imbi12d 348 . . . . . 6 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → ((¬ ∀𝑥 𝑥 = 𝑤 → (𝑥 = 𝑤 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑤 → ∀𝑧𝜑)))) ↔ (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))))
193, 18mpbii 236 . . . . 5 ((¬ ∀𝑥 𝑥 = 𝑦𝑤 = 𝑦) → (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑)))))
2019ex 416 . . . 4 (¬ ∀𝑥 𝑥 = 𝑦 → (𝑤 = 𝑦 → (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))))
2120exlimdv 1934 . . 3 (¬ ∀𝑥 𝑥 = 𝑦 → (∃𝑤 𝑤 = 𝑦 → (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))))
221, 21mpi 20 . 2 (¬ ∀𝑥 𝑥 = 𝑦 → (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑)))))
2322pm2.43i 52 1 (¬ ∀𝑥 𝑥 = 𝑦 → (𝑥 = 𝑦 → (∀𝑧𝜑 → ∀𝑥(𝑥 = 𝑦 → ∀𝑧𝜑))))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ↔ wb 209   ∧ wa 399  ∀wal 1536  ∃wex 1781 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-10 2142  ax-11 2158  ax-12 2175  ax-13 2379  ax-c5 36198  ax-c4 36199  ax-c7 36200  ax-c10 36201  ax-c11 36202  ax-c9 36205  ax-c16 36207 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-tru 1541  df-ex 1782  df-nf 1786 This theorem is referenced by: (None)
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