Theorem rngoideu 36766

Description: The unity element of a ring is unique. (Contributed by NM, 4-Apr-2009.) (Revised by Mario Carneiro, 21-Dec-2013.) (New usage is discouraged.)

Hypotheses

Ref	Expression
ringi.1	⊢ 𝐺 = (1st ‘𝑅)
ringi.2	⊢ 𝐻 = (2nd ‘𝑅)
ringi.3	⊢ 𝑋 = ran 𝐺

Assertion

Ref	Expression
rngoideu	⊢ (𝑅 ∈ RingOps → ∃!𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥))

Distinct variable groups:   𝑥,𝑢,𝐺   𝑢,𝐻,𝑥   𝑢,𝑋,𝑥   𝑢,𝑅,𝑥

Proof of Theorem rngoideu

Dummy variable 𝑦 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		ringi.1	. . . 4 ⊢ 𝐺 = (1st ‘𝑅)
2		ringi.2	. . . 4 ⊢ 𝐻 = (2nd ‘𝑅)
3		ringi.3	. . . 4 ⊢ 𝑋 = ran 𝐺
4	1, 2, 3	rngoi 36762	. . 3 ⊢ (𝑅 ∈ RingOps → ((𝐺 ∈ AbelOp ∧ 𝐻:(𝑋 × 𝑋)⟶𝑋) ∧ (∀𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ∀𝑦 ∈ 𝑋 (((𝑢𝐻𝑥)𝐻𝑦) = (𝑢𝐻(𝑥𝐻𝑦)) ∧ (𝑢𝐻(𝑥𝐺𝑦)) = ((𝑢𝐻𝑥)𝐺(𝑢𝐻𝑦)) ∧ ((𝑢𝐺𝑥)𝐻𝑦) = ((𝑢𝐻𝑦)𝐺(𝑥𝐻𝑦))) ∧ ∃𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥))))
5	4	simprrd 772	. 2 ⊢ (𝑅 ∈ RingOps → ∃𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥))
6		simpl 483	. . . . . . 7 ⊢ (((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) → (𝑢𝐻𝑥) = 𝑥)
7	6	ralimi 3083	. . . . . 6 ⊢ (∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) → ∀𝑥 ∈ 𝑋 (𝑢𝐻𝑥) = 𝑥)
8		oveq2 7416	. . . . . . . 8 ⊢ (𝑥 = 𝑦 → (𝑢𝐻𝑥) = (𝑢𝐻𝑦))
9		id 22	. . . . . . . 8 ⊢ (𝑥 = 𝑦 → 𝑥 = 𝑦)
10	8, 9	eqeq12d 2748	. . . . . . 7 ⊢ (𝑥 = 𝑦 → ((𝑢𝐻𝑥) = 𝑥 ↔ (𝑢𝐻𝑦) = 𝑦))
11	10	rspcv 3608	. . . . . 6 ⊢ (𝑦 ∈ 𝑋 → (∀𝑥 ∈ 𝑋 (𝑢𝐻𝑥) = 𝑥 → (𝑢𝐻𝑦) = 𝑦))
12	7, 11	syl5 34	. . . . 5 ⊢ (𝑦 ∈ 𝑋 → (∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) → (𝑢𝐻𝑦) = 𝑦))
13		simpr 485	. . . . . . 7 ⊢ (((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥) → (𝑥𝐻𝑦) = 𝑥)
14	13	ralimi 3083	. . . . . 6 ⊢ (∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥) → ∀𝑥 ∈ 𝑋 (𝑥𝐻𝑦) = 𝑥)
15		oveq1 7415	. . . . . . . 8 ⊢ (𝑥 = 𝑢 → (𝑥𝐻𝑦) = (𝑢𝐻𝑦))
16		id 22	. . . . . . . 8 ⊢ (𝑥 = 𝑢 → 𝑥 = 𝑢)
17	15, 16	eqeq12d 2748	. . . . . . 7 ⊢ (𝑥 = 𝑢 → ((𝑥𝐻𝑦) = 𝑥 ↔ (𝑢𝐻𝑦) = 𝑢))
18	17	rspcv 3608	. . . . . 6 ⊢ (𝑢 ∈ 𝑋 → (∀𝑥 ∈ 𝑋 (𝑥𝐻𝑦) = 𝑥 → (𝑢𝐻𝑦) = 𝑢))
19	14, 18	syl5 34	. . . . 5 ⊢ (𝑢 ∈ 𝑋 → (∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥) → (𝑢𝐻𝑦) = 𝑢))
20	12, 19	im2anan9r 621	. . . 4 ⊢ ((𝑢 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → ((∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ∧ ∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥)) → ((𝑢𝐻𝑦) = 𝑦 ∧ (𝑢𝐻𝑦) = 𝑢)))
21		eqtr2 2756	. . . . 5 ⊢ (((𝑢𝐻𝑦) = 𝑦 ∧ (𝑢𝐻𝑦) = 𝑢) → 𝑦 = 𝑢)
22	21	equcomd 2022	. . . 4 ⊢ (((𝑢𝐻𝑦) = 𝑦 ∧ (𝑢𝐻𝑦) = 𝑢) → 𝑢 = 𝑦)
23	20, 22	syl6 35	. . 3 ⊢ ((𝑢 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋) → ((∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ∧ ∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥)) → 𝑢 = 𝑦))
24	23	rgen2 3197	. 2 ⊢ ∀𝑢 ∈ 𝑋 ∀𝑦 ∈ 𝑋 ((∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ∧ ∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥)) → 𝑢 = 𝑦)
25		oveq1 7415	. . . . 5 ⊢ (𝑢 = 𝑦 → (𝑢𝐻𝑥) = (𝑦𝐻𝑥))
26	25	eqeq1d 2734	. . . 4 ⊢ (𝑢 = 𝑦 → ((𝑢𝐻𝑥) = 𝑥 ↔ (𝑦𝐻𝑥) = 𝑥))
27	26	ovanraleqv 7432	. . 3 ⊢ (𝑢 = 𝑦 → (∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ↔ ∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥)))
28	27	reu4 3727	. 2 ⊢ (∃!𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ↔ (∃𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ∧ ∀𝑢 ∈ 𝑋 ∀𝑦 ∈ 𝑋 ((∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥) ∧ ∀𝑥 ∈ 𝑋 ((𝑦𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑦) = 𝑥)) → 𝑢 = 𝑦)))
29	5, 24, 28	sylanblrc 590	1 ⊢ (𝑅 ∈ RingOps → ∃!𝑢 ∈ 𝑋 ∀𝑥 ∈ 𝑋 ((𝑢𝐻𝑥) = 𝑥 ∧ (𝑥𝐻𝑢) = 𝑥))

Syntax hints:   → wi 4   ∧ wa 396   ∧ w3a 1087   = wceq 1541   ∈ wcel 2106  ∀wral 3061  ∃wrex 3070  ∃!wreu 3374   × cxp 5674  ran crn 5677  ⟶wf 6539  ‘cfv 6543  (class class class)co 7408  1^st c1st 7972  2^nd c2nd 7973  AbelOpcablo 29792  RingOpscrngo 36757

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 1913  ax-6 1971  ax-7 2011  ax-8 2108  ax-9 2116  ax-10 2137  ax-11 2154  ax-12 2171  ax-ext 2703  ax-sep 5299  ax-nul 5306  ax-pr 5427  ax-un 7724

This theorem depends on definitions:  df-bi 206  df-an 397  df-or 846  df-3an 1089  df-tru 1544  df-fal 1554  df-ex 1782  df-nf 1786  df-sb 2068  df-mo 2534  df-eu 2563  df-clab 2710  df-cleq 2724  df-clel 2810  df-nfc 2885  df-ne 2941  df-ral 3062  df-rex 3071  df-rmo 3376  df-reu 3377  df-rab 3433  df-v 3476  df-dif 3951  df-un 3953  df-in 3955  df-ss 3965  df-nul 4323  df-if 4529  df-sn 4629  df-pr 4631  df-op 4635  df-uni 4909  df-br 5149  df-opab 5211  df-mpt 5232  df-id 5574  df-xp 5682  df-rel 5683  df-cnv 5684  df-co 5685  df-dm 5686  df-rn 5687  df-iota 6495  df-fun 6545  df-fn 6546  df-f 6547  df-fv 6551  df-ov 7411  df-1st 7974  df-2nd 7975  df-rngo 36758

This theorem is referenced by: (None)