Theorem equveli 1682

Description: A variable elimination law for equality with no distinct variable requirements. (Compare equvini 1681.) (Contributed by NM, 1-Mar-2013.) (Revised by NM, 3-Feb-2015.)

Assertion

Ref	Expression
equveli	⊢ (∀𝑧(𝑧 = 𝑥 ↔ 𝑧 = 𝑦) → 𝑥 = 𝑦)

Proof of Theorem equveli

Step	Hyp	Ref	Expression
1		albiim 1416	. 2 ⊢ (∀𝑧(𝑧 = 𝑥 ↔ 𝑧 = 𝑦) ↔ (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)))
2		ax12or 1443	. . 3 ⊢ (∀𝑧 𝑧 = 𝑥 ∨ (∀𝑧 𝑧 = 𝑦 ∨ ∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦)))
3		equequ1 1638	. . . . . . . . 9 ⊢ (𝑧 = 𝑥 → (𝑧 = 𝑥 ↔ 𝑥 = 𝑥))
4		equequ1 1638	. . . . . . . . 9 ⊢ (𝑧 = 𝑥 → (𝑧 = 𝑦 ↔ 𝑥 = 𝑦))
5	3, 4	imbi12d 232	. . . . . . . 8 ⊢ (𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) ↔ (𝑥 = 𝑥 → 𝑥 = 𝑦)))
6	5	sps 1470	. . . . . . 7 ⊢ (∀𝑧 𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) ↔ (𝑥 = 𝑥 → 𝑥 = 𝑦)))
7	6	dral2 1659	. . . . . 6 ⊢ (∀𝑧 𝑧 = 𝑥 → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ↔ ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)))
8		equid 1629	. . . . . . . . 9 ⊢ 𝑥 = 𝑥
9	8	a1bi 241	. . . . . . . 8 ⊢ (𝑥 = 𝑦 ↔ (𝑥 = 𝑥 → 𝑥 = 𝑦))
10	9	biimpri 131	. . . . . . 7 ⊢ ((𝑥 = 𝑥 → 𝑥 = 𝑦) → 𝑥 = 𝑦)
11	10	sps 1470	. . . . . 6 ⊢ (∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦) → 𝑥 = 𝑦)
12	7, 11	syl6bi 161	. . . . 5 ⊢ (∀𝑧 𝑧 = 𝑥 → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) → 𝑥 = 𝑦))
13	12	adantrd 273	. . . 4 ⊢ (∀𝑧 𝑧 = 𝑥 → ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦))
14		equequ1 1638	. . . . . . . . . 10 ⊢ (𝑧 = 𝑦 → (𝑧 = 𝑦 ↔ 𝑦 = 𝑦))
15		equequ1 1638	. . . . . . . . . 10 ⊢ (𝑧 = 𝑦 → (𝑧 = 𝑥 ↔ 𝑦 = 𝑥))
16	14, 15	imbi12d 232	. . . . . . . . 9 ⊢ (𝑧 = 𝑦 → ((𝑧 = 𝑦 → 𝑧 = 𝑥) ↔ (𝑦 = 𝑦 → 𝑦 = 𝑥)))
17	16	sps 1470	. . . . . . . 8 ⊢ (∀𝑧 𝑧 = 𝑦 → ((𝑧 = 𝑦 → 𝑧 = 𝑥) ↔ (𝑦 = 𝑦 → 𝑦 = 𝑥)))
18	17	dral1 1658	. . . . . . 7 ⊢ (∀𝑧 𝑧 = 𝑦 → (∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥) ↔ ∀𝑦(𝑦 = 𝑦 → 𝑦 = 𝑥)))
19		equid 1629	. . . . . . . . 9 ⊢ 𝑦 = 𝑦
20		ax-4 1440	. . . . . . . . 9 ⊢ (∀𝑦(𝑦 = 𝑦 → 𝑦 = 𝑥) → (𝑦 = 𝑦 → 𝑦 = 𝑥))
21	19, 20	mpi 15	. . . . . . . 8 ⊢ (∀𝑦(𝑦 = 𝑦 → 𝑦 = 𝑥) → 𝑦 = 𝑥)
22		equcomi 1632	. . . . . . . 8 ⊢ (𝑦 = 𝑥 → 𝑥 = 𝑦)
23	21, 22	syl 14	. . . . . . 7 ⊢ (∀𝑦(𝑦 = 𝑦 → 𝑦 = 𝑥) → 𝑥 = 𝑦)
24	18, 23	syl6bi 161	. . . . . 6 ⊢ (∀𝑧 𝑧 = 𝑦 → (∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥) → 𝑥 = 𝑦))
25	24	adantld 272	. . . . 5 ⊢ (∀𝑧 𝑧 = 𝑦 → ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦))
26		hba1 1473	. . . . . . . . . 10 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → ∀𝑧∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦))
27		hbequid 1446	. . . . . . . . . . 11 ⊢ (𝑥 = 𝑥 → ∀𝑧 𝑥 = 𝑥)
28	27	a1i 9	. . . . . . . . . 10 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → (𝑥 = 𝑥 → ∀𝑧 𝑥 = 𝑥))
29		ax-4 1440	. . . . . . . . . 10 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → (𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦))
30	26, 28, 29	hbimd 1505	. . . . . . . . 9 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → ((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)))
31	30	a5i 1475	. . . . . . . 8 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → ∀𝑧((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)))
32		equtr 1635	. . . . . . . . . 10 ⊢ (𝑧 = 𝑥 → (𝑥 = 𝑥 → 𝑧 = 𝑥))
33		ax-8 1435	. . . . . . . . . 10 ⊢ (𝑧 = 𝑥 → (𝑧 = 𝑦 → 𝑥 = 𝑦))
34	32, 33	imim12d 73	. . . . . . . . 9 ⊢ (𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))
35	34	ax-gen 1378	. . . . . . . 8 ⊢ ∀𝑧(𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))
36		19.26 1410	. . . . . . . . 9 ⊢ (∀𝑧(((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)) ∧ (𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))) ↔ (∀𝑧((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)) ∧ ∀𝑧(𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))))
37		spimth 1663	. . . . . . . . 9 ⊢ (∀𝑧(((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)) ∧ (𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))) → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))
38	36, 37	sylbir 133	. . . . . . . 8 ⊢ ((∀𝑧((𝑥 = 𝑥 → 𝑥 = 𝑦) → ∀𝑧(𝑥 = 𝑥 → 𝑥 = 𝑦)) ∧ ∀𝑧(𝑧 = 𝑥 → ((𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))) → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))
39	31, 35, 38	sylancl 404	. . . . . . 7 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) → (𝑥 = 𝑥 → 𝑥 = 𝑦)))
40	8, 39	mpii 43	. . . . . 6 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → (∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) → 𝑥 = 𝑦))
41	40	adantrd 273	. . . . 5 ⊢ (∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦) → ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦))
42	25, 41	jaoi 668	. . . 4 ⊢ ((∀𝑧 𝑧 = 𝑦 ∨ ∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦)) → ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦))
43	13, 42	jaoi 668	. . 3 ⊢ ((∀𝑧 𝑧 = 𝑥 ∨ (∀𝑧 𝑧 = 𝑦 ∨ ∀𝑧(𝑥 = 𝑦 → ∀𝑧 𝑥 = 𝑦))) → ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦))
44	2, 43	ax-mp 7	. 2 ⊢ ((∀𝑧(𝑧 = 𝑥 → 𝑧 = 𝑦) ∧ ∀𝑧(𝑧 = 𝑦 → 𝑧 = 𝑥)) → 𝑥 = 𝑦)
45	1, 44	sylbi 119	1 ⊢ (∀𝑧(𝑧 = 𝑥 ↔ 𝑧 = 𝑦) → 𝑥 = 𝑦)

Syntax hints:   → wi 4   ∧ wa 102   ↔ wb 103   ∨ wo 661  ∀wal 1282   = wceq 1284

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-io 662  ax-5 1376  ax-7 1377  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-8 1435  ax-10 1436  ax-11 1437  ax-i12 1438  ax-4 1440  ax-17 1459  ax-i9 1463  ax-ial 1467  ax-i5r 1468

This theorem depends on definitions:  df-bi 115

This theorem is referenced by: (None)