Theorem wfrlem5 7942

Description: Lemma for well-founded recursion. The values of two acceptable functions agree within their domains. (Contributed by Scott Fenton, 21-Apr-2011.) (Revised by Mario Carneiro, 26-Jun-2015.)

Hypotheses

Ref	Expression
wfrlem5.1	⊢ 𝑅 We 𝐴
wfrlem5.2	⊢ 𝑅 Se 𝐴
wfrlem5.3	⊢ 𝐵 = {𝑓 ∣ ∃𝑥(𝑓 Fn 𝑥 ∧ (𝑥 ⊆ 𝐴 ∧ ∀𝑦 ∈ 𝑥 Pred(𝑅, 𝐴, 𝑦) ⊆ 𝑥) ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ Pred(𝑅, 𝐴, 𝑦))))}

Assertion

Ref	Expression
wfrlem5	⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣) → 𝑢 = 𝑣))

Distinct variable groups:   𝐴,𝑓,𝑔,ℎ,𝑥,𝑦   𝑓,𝐹,𝑔,ℎ,𝑥,𝑦   𝑅,𝑓,𝑔,ℎ,𝑥,𝑦   𝑢,𝑔,𝑣,ℎ,𝑥

Allowed substitution hints:   𝐴(𝑣,𝑢)   𝐵(𝑥,𝑦,𝑣,𝑢,𝑓,𝑔,ℎ)   𝑅(𝑣,𝑢)   𝐹(𝑣,𝑢)

Proof of Theorem wfrlem5

Dummy variable 𝑎 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		vex 3444	. . . . . 6 ⊢ 𝑥 ∈ V
2		vex 3444	. . . . . 6 ⊢ 𝑢 ∈ V
3	1, 2	breldm 5741	. . . . 5 ⊢ (𝑥𝑔𝑢 → 𝑥 ∈ dom 𝑔)
4		vex 3444	. . . . . 6 ⊢ 𝑣 ∈ V
5	1, 4	breldm 5741	. . . . 5 ⊢ (𝑥ℎ𝑣 → 𝑥 ∈ dom ℎ)
6	3, 5	anim12i 615	. . . 4 ⊢ ((𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣) → (𝑥 ∈ dom 𝑔 ∧ 𝑥 ∈ dom ℎ))
7		elin 3897	. . . 4 ⊢ (𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ↔ (𝑥 ∈ dom 𝑔 ∧ 𝑥 ∈ dom ℎ))
8	6, 7	sylibr 237	. . 3 ⊢ ((𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣) → 𝑥 ∈ (dom 𝑔 ∩ dom ℎ))
9		anandi 675	. . . 4 ⊢ ((𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ (𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣)) ↔ ((𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥𝑔𝑢) ∧ (𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥ℎ𝑣)))
10	2	brresi 5827	. . . . 5 ⊢ (𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ↔ (𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥𝑔𝑢))
11	4	brresi 5827	. . . . 5 ⊢ (𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣 ↔ (𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥ℎ𝑣))
12	10, 11	anbi12i 629	. . . 4 ⊢ ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣) ↔ ((𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥𝑔𝑢) ∧ (𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ 𝑥ℎ𝑣)))
13	9, 12	sylbb2 241	. . 3 ⊢ ((𝑥 ∈ (dom 𝑔 ∩ dom ℎ) ∧ (𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣)) → (𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣))
14	8, 13	mpancom 687	. 2 ⊢ ((𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣) → (𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣))
15		wfrlem5.3	. . . . . . . . 9 ⊢ 𝐵 = {𝑓 ∣ ∃𝑥(𝑓 Fn 𝑥 ∧ (𝑥 ⊆ 𝐴 ∧ ∀𝑦 ∈ 𝑥 Pred(𝑅, 𝐴, 𝑦) ⊆ 𝑥) ∧ ∀𝑦 ∈ 𝑥 (𝑓‘𝑦) = (𝐹‘(𝑓 ↾ Pred(𝑅, 𝐴, 𝑦))))}
16	15	wfrlem3 7939	. . . . . . . 8 ⊢ (𝑔 ∈ 𝐵 → dom 𝑔 ⊆ 𝐴)
17		ssinss1 4164	. . . . . . . 8 ⊢ (dom 𝑔 ⊆ 𝐴 → (dom 𝑔 ∩ dom ℎ) ⊆ 𝐴)
18		wfrlem5.1	. . . . . . . . . 10 ⊢ 𝑅 We 𝐴
19		wess 5506	. . . . . . . . . 10 ⊢ ((dom 𝑔 ∩ dom ℎ) ⊆ 𝐴 → (𝑅 We 𝐴 → 𝑅 We (dom 𝑔 ∩ dom ℎ)))
20	18, 19	mpi 20	. . . . . . . . 9 ⊢ ((dom 𝑔 ∩ dom ℎ) ⊆ 𝐴 → 𝑅 We (dom 𝑔 ∩ dom ℎ))
21		wfrlem5.2	. . . . . . . . . 10 ⊢ 𝑅 Se 𝐴
22		sess2 5488	. . . . . . . . . 10 ⊢ ((dom 𝑔 ∩ dom ℎ) ⊆ 𝐴 → (𝑅 Se 𝐴 → 𝑅 Se (dom 𝑔 ∩ dom ℎ)))
23	21, 22	mpi 20	. . . . . . . . 9 ⊢ ((dom 𝑔 ∩ dom ℎ) ⊆ 𝐴 → 𝑅 Se (dom 𝑔 ∩ dom ℎ))
24	20, 23	jca 515	. . . . . . . 8 ⊢ ((dom 𝑔 ∩ dom ℎ) ⊆ 𝐴 → (𝑅 We (dom 𝑔 ∩ dom ℎ) ∧ 𝑅 Se (dom 𝑔 ∩ dom ℎ)))
25	16, 17, 24	3syl 18	. . . . . . 7 ⊢ (𝑔 ∈ 𝐵 → (𝑅 We (dom 𝑔 ∩ dom ℎ) ∧ 𝑅 Se (dom 𝑔 ∩ dom ℎ)))
26	25	adantr 484	. . . . . 6 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → (𝑅 We (dom 𝑔 ∩ dom ℎ) ∧ 𝑅 Se (dom 𝑔 ∩ dom ℎ)))
27	15	wfrlem4 7941	. . . . . 6 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ∧ ∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((𝑔 ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎)))))
28	15	wfrlem4 7941	. . . . . . . 8 ⊢ ((ℎ ∈ 𝐵 ∧ 𝑔 ∈ 𝐵) → ((ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom ℎ ∩ dom 𝑔) ∧ ∀𝑎 ∈ (dom ℎ ∩ dom 𝑔)((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎)))))
29	28	ancoms 462	. . . . . . 7 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom ℎ ∩ dom 𝑔) ∧ ∀𝑎 ∈ (dom ℎ ∩ dom 𝑔)((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎)))))
30		incom 4128	. . . . . . . . . . 11 ⊢ (dom 𝑔 ∩ dom ℎ) = (dom ℎ ∩ dom 𝑔)
31	30	reseq2i 5815	. . . . . . . . . 10 ⊢ (ℎ ↾ (dom 𝑔 ∩ dom ℎ)) = (ℎ ↾ (dom ℎ ∩ dom 𝑔))
32	31	fneq1i 6420	. . . . . . . . 9 ⊢ ((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ↔ (ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom 𝑔 ∩ dom ℎ))
33	30	fneq2i 6421	. . . . . . . . 9 ⊢ ((ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom 𝑔 ∩ dom ℎ) ↔ (ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom ℎ ∩ dom 𝑔))
34	32, 33	bitri 278	. . . . . . . 8 ⊢ ((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ↔ (ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom ℎ ∩ dom 𝑔))
35	31	fveq1i 6646	. . . . . . . . . 10 ⊢ ((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = ((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎)
36		predeq2 6119	. . . . . . . . . . . . 13 ⊢ ((dom 𝑔 ∩ dom ℎ) = (dom ℎ ∩ dom 𝑔) → Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎) = Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎))
37	30, 36	ax-mp 5	. . . . . . . . . . . 12 ⊢ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎) = Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎)
38	31, 37	reseq12i 5816	. . . . . . . . . . 11 ⊢ ((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎)) = ((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎))
39	38	fveq2i 6648	. . . . . . . . . 10 ⊢ (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎))) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎)))
40	35, 39	eqeq12i 2813	. . . . . . . . 9 ⊢ (((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎))) ↔ ((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎))))
41	30, 40	raleqbii 3197	. . . . . . . 8 ⊢ (∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎))) ↔ ∀𝑎 ∈ (dom ℎ ∩ dom 𝑔)((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎))))
42	34, 41	anbi12i 629	. . . . . . 7 ⊢ (((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ∧ ∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎)))) ↔ ((ℎ ↾ (dom ℎ ∩ dom 𝑔)) Fn (dom ℎ ∩ dom 𝑔) ∧ ∀𝑎 ∈ (dom ℎ ∩ dom 𝑔)((ℎ ↾ (dom ℎ ∩ dom 𝑔))‘𝑎) = (𝐹‘((ℎ ↾ (dom ℎ ∩ dom 𝑔)) ↾ Pred(𝑅, (dom ℎ ∩ dom 𝑔), 𝑎)))))
43	29, 42	sylibr 237	. . . . . 6 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ∧ ∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎)))))
44		wfr3g 7936	. . . . . 6 ⊢ (((𝑅 We (dom 𝑔 ∩ dom ℎ) ∧ 𝑅 Se (dom 𝑔 ∩ dom ℎ)) ∧ ((𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ∧ ∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((𝑔 ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎)))) ∧ ((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) Fn (dom 𝑔 ∩ dom ℎ) ∧ ∀𝑎 ∈ (dom 𝑔 ∩ dom ℎ)((ℎ ↾ (dom 𝑔 ∩ dom ℎ))‘𝑎) = (𝐹‘((ℎ ↾ (dom 𝑔 ∩ dom ℎ)) ↾ Pred(𝑅, (dom 𝑔 ∩ dom ℎ), 𝑎))))) → (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) = (ℎ ↾ (dom 𝑔 ∩ dom ℎ)))
45	26, 27, 43, 44	syl3anc 1368	. . . . 5 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) = (ℎ ↾ (dom 𝑔 ∩ dom ℎ)))
46	45	breqd 5041	. . . 4 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → (𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣 ↔ 𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣))
47	46	biimprd 251	. . 3 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → (𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣 → 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣))
48	15	wfrlem2 7938	. . . . 5 ⊢ (𝑔 ∈ 𝐵 → Fun 𝑔)
49		funres 6366	. . . . 5 ⊢ (Fun 𝑔 → Fun (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)))
50		dffun2 6334	. . . . . 6 ⊢ (Fun (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) ↔ (Rel (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) ∧ ∀𝑥∀𝑢∀𝑣((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣)))
51	50	simprbi 500	. . . . 5 ⊢ (Fun (𝑔 ↾ (dom 𝑔 ∩ dom ℎ)) → ∀𝑥∀𝑢∀𝑣((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
52		2sp 2183	. . . . . 6 ⊢ (∀𝑢∀𝑣((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣) → ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
53	52	sps 2182	. . . . 5 ⊢ (∀𝑥∀𝑢∀𝑣((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣) → ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
54	48, 49, 51, 53	4syl 19	. . . 4 ⊢ (𝑔 ∈ 𝐵 → ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
55	54	adantr 484	. . 3 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
56	47, 55	sylan2d 607	. 2 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((𝑥(𝑔 ↾ (dom 𝑔 ∩ dom ℎ))𝑢 ∧ 𝑥(ℎ ↾ (dom 𝑔 ∩ dom ℎ))𝑣) → 𝑢 = 𝑣))
57	14, 56	syl5 34	1 ⊢ ((𝑔 ∈ 𝐵 ∧ ℎ ∈ 𝐵) → ((𝑥𝑔𝑢 ∧ 𝑥ℎ𝑣) → 𝑢 = 𝑣))

Syntax hints:   → wi 4   ∧ wa 399   ∧ w3a 1084  ∀wal 1536   = wceq 1538  ∃wex 1781   ∈ wcel 2111  {cab 2776  ∀wral 3106   ∩ cin 3880   ⊆ wss 3881   class class class wbr 5030   Se wse 5476   We wwe 5477  dom cdm 5519   ↾ cres 5521  Rel wrel 5524  Predcpred 6115  Fun wfun 6318   Fn wfn 6319  ‘cfv 6324

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-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770  ax-sep 5167  ax-nul 5174  ax-pow 5231  ax-pr 5295

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3or 1085  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2598  df-eu 2629  df-clab 2777  df-cleq 2791  df-clel 2870  df-nfc 2938  df-ne 2988  df-ral 3111  df-rex 3112  df-reu 3113  df-rmo 3114  df-rab 3115  df-v 3443  df-sbc 3721  df-csb 3829  df-dif 3884  df-un 3886  df-in 3888  df-ss 3898  df-nul 4244  df-if 4426  df-sn 4526  df-pr 4528  df-op 4532  df-uni 4801  df-br 5031  df-opab 5093  df-mpt 5111  df-id 5425  df-po 5438  df-so 5439  df-fr 5478  df-se 5479  df-we 5480  df-xp 5525  df-rel 5526  df-cnv 5527  df-co 5528  df-dm 5529  df-rn 5530  df-res 5531  df-ima 5532  df-pred 6116  df-iota 6283  df-fun 6326  df-fn 6327  df-fv 6332

This theorem is referenced by:  wfrfun  7948