Theorem addsasslem2 28234

Description: Lemma for addition associativity. Expand the other form of the triple sum. (Contributed by Scott Fenton, 21-Jan-2025.)

Hypotheses

Ref	Expression
addsasslem.1	⊢ (𝜑 → 𝐴 ∈ No )
addsasslem.2	⊢ (𝜑 → 𝐵 ∈ No )
addsasslem.3	⊢ (𝜑 → 𝐶 ∈ No )

Assertion

Ref	Expression
addsasslem2	⊢ (𝜑 → (𝐴 +s (𝐵 +s 𝐶)) = ((({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))}) ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}) |s (({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))}) ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))})))

Distinct variable groups:   𝐴,𝑎,𝑏,𝑐,𝑙,𝑚,𝑛,𝑝,𝑞,𝑟,𝑤,𝑦,𝑧   𝐵,𝑎,𝑏,𝑐,𝑙,𝑚,𝑛,𝑝,𝑞,𝑟,𝑤,𝑦,𝑧   𝐶,𝑎,𝑏,𝑐,𝑙,𝑚,𝑛,𝑝,𝑞,𝑟,𝑤,𝑦,𝑧   𝜑,𝑎,𝑏,𝑐,𝑙,𝑚,𝑛,𝑝,𝑞,𝑟,𝑤,𝑦,𝑧

Proof of Theorem addsasslem2

Dummy variables 𝑑 𝑒 𝑓 𝑔 ℎ 𝑖 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		lltr 28092	. . . 4 ⊢ ( L ‘𝐴) <<s ( R ‘𝐴)
2	1	a1i 11	. . 3 ⊢ (𝜑 → ( L ‘𝐴) <<s ( R ‘𝐴))
3		addsasslem.2	. . . . . 6 ⊢ (𝜑 → 𝐵 ∈ No )
4		addsasslem.3	. . . . . 6 ⊢ (𝜑 → 𝐶 ∈ No )
5	3, 4	addcuts 28208	. . . . 5 ⊢ (𝜑 → ((𝐵 +s 𝐶) ∈ No ∧ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s {(𝐵 +s 𝐶)} ∧ {(𝐵 +s 𝐶)} <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})))
6	5	simp2d 1161	. . . 4 ⊢ (𝜑 → ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s {(𝐵 +s 𝐶)})
7	5	simp3d 1162	. . . 4 ⊢ (𝜑 → {(𝐵 +s 𝐶)} <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}))
8		ovex 7456	. . . . . 6 ⊢ (𝐵 +s 𝐶) ∈ V
9	8	snnz 4747	. . . . 5 ⊢ {(𝐵 +s 𝐶)} ≠ ∅
10		sltstr 28017	. . . . 5 ⊢ ((({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s {(𝐵 +s 𝐶)} ∧ {(𝐵 +s 𝐶)} <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}) ∧ {(𝐵 +s 𝐶)} ≠ ∅) → ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}))
11	9, 10	mp3an3 1479	. . . 4 ⊢ ((({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s {(𝐵 +s 𝐶)} ∧ {(𝐵 +s 𝐶)} <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})) → ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}))
12	6, 7, 11	syl2anc 596	. . 3 ⊢ (𝜑 → ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) <<s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}))
13		addsasslem.1	. . . . 5 ⊢ (𝜑 → 𝐴 ∈ No )
14		lrcut 28134	. . . . 5 ⊢ (𝐴 ∈ No → (( L ‘𝐴) |s ( R ‘𝐴)) = 𝐴)
15	13, 14	syl 18	. . . 4 ⊢ (𝜑 → (( L ‘𝐴) |s ( R ‘𝐴)) = 𝐴)
16	15	eqcomd 2772	. . 3 ⊢ (𝜑 → 𝐴 = (( L ‘𝐴) |s ( R ‘𝐴)))
17		addsval2 28193	. . . 4 ⊢ ((𝐵 ∈ No ∧ 𝐶 ∈ No ) → (𝐵 +s 𝐶) = (({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) |s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})))
18	3, 4, 17	syl2anc 596	. . 3 ⊢ (𝜑 → (𝐵 +s 𝐶) = (({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}) |s ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})))
19	2, 12, 16, 18	addsunif 28232	. 2 ⊢ (𝜑 → (𝐴 +s (𝐵 +s 𝐶)) = (({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)}) |s ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)})))
20		rexun 4152	. . . . . . . 8 ⊢ (∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ) ↔ (∃ℎ ∈ {𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)}𝑧 = (𝐴 +s ℎ) ∨ ∃ℎ ∈ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}𝑧 = (𝐴 +s ℎ)))
21		eqeq1 2770	. . . . . . . . . . . 12 ⊢ (𝑑 = ℎ → (𝑑 = (𝑚 +s 𝐶) ↔ ℎ = (𝑚 +s 𝐶)))
22	21	rexbidv 3192	. . . . . . . . . . 11 ⊢ (𝑑 = ℎ → (∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶) ↔ ∃𝑚 ∈ ( L ‘𝐵)ℎ = (𝑚 +s 𝐶)))
23	22	rexab 3661	. . . . . . . . . 10 ⊢ (∃ℎ ∈ {𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)}𝑧 = (𝐴 +s ℎ) ↔ ∃ℎ(∃𝑚 ∈ ( L ‘𝐵)ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)))
24		rexcom4 3295	. . . . . . . . . . 11 ⊢ (∃𝑚 ∈ ( L ‘𝐵)∃ℎ(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃ℎ∃𝑚 ∈ ( L ‘𝐵)(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)))
25		ovex 7456	. . . . . . . . . . . . 13 ⊢ (𝑚 +s 𝐶) ∈ V
26		oveq2 7431	. . . . . . . . . . . . . 14 ⊢ (ℎ = (𝑚 +s 𝐶) → (𝐴 +s ℎ) = (𝐴 +s (𝑚 +s 𝐶)))
27	26	eqeq2d 2777	. . . . . . . . . . . . 13 ⊢ (ℎ = (𝑚 +s 𝐶) → (𝑧 = (𝐴 +s ℎ) ↔ 𝑧 = (𝐴 +s (𝑚 +s 𝐶))))
28	25, 27	ceqsexv 3506	. . . . . . . . . . . 12 ⊢ (∃ℎ(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ 𝑧 = (𝐴 +s (𝑚 +s 𝐶)))
29	28	rexbii 3115	. . . . . . . . . . 11 ⊢ (∃𝑚 ∈ ( L ‘𝐵)∃ℎ(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)))
30		r19.41v 3198	. . . . . . . . . . . 12 ⊢ (∃𝑚 ∈ ( L ‘𝐵)(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ (∃𝑚 ∈ ( L ‘𝐵)ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)))
31	30	exbii 1881	. . . . . . . . . . 11 ⊢ (∃ℎ∃𝑚 ∈ ( L ‘𝐵)(ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃ℎ(∃𝑚 ∈ ( L ‘𝐵)ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)))
32	24, 29, 31	3bitr3ri 305	. . . . . . . . . 10 ⊢ (∃ℎ(∃𝑚 ∈ ( L ‘𝐵)ℎ = (𝑚 +s 𝐶) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)))
33	23, 32	bitri 278	. . . . . . . . 9 ⊢ (∃ℎ ∈ {𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)}𝑧 = (𝐴 +s ℎ) ↔ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)))
34		eqeq1 2770	. . . . . . . . . . . 12 ⊢ (𝑒 = ℎ → (𝑒 = (𝐵 +s 𝑛) ↔ ℎ = (𝐵 +s 𝑛)))
35	34	rexbidv 3192	. . . . . . . . . . 11 ⊢ (𝑒 = ℎ → (∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛) ↔ ∃𝑛 ∈ ( L ‘𝐶)ℎ = (𝐵 +s 𝑛)))
36	35	rexab 3661	. . . . . . . . . 10 ⊢ (∃ℎ ∈ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}𝑧 = (𝐴 +s ℎ) ↔ ∃ℎ(∃𝑛 ∈ ( L ‘𝐶)ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)))
37		rexcom4 3295	. . . . . . . . . . 11 ⊢ (∃𝑛 ∈ ( L ‘𝐶)∃ℎ(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃ℎ∃𝑛 ∈ ( L ‘𝐶)(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)))
38		ovex 7456	. . . . . . . . . . . . 13 ⊢ (𝐵 +s 𝑛) ∈ V
39		oveq2 7431	. . . . . . . . . . . . . 14 ⊢ (ℎ = (𝐵 +s 𝑛) → (𝐴 +s ℎ) = (𝐴 +s (𝐵 +s 𝑛)))
40	39	eqeq2d 2777	. . . . . . . . . . . . 13 ⊢ (ℎ = (𝐵 +s 𝑛) → (𝑧 = (𝐴 +s ℎ) ↔ 𝑧 = (𝐴 +s (𝐵 +s 𝑛))))
41	38, 40	ceqsexv 3506	. . . . . . . . . . . 12 ⊢ (∃ℎ(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ 𝑧 = (𝐴 +s (𝐵 +s 𝑛)))
42	41	rexbii 3115	. . . . . . . . . . 11 ⊢ (∃𝑛 ∈ ( L ‘𝐶)∃ℎ(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)))
43		r19.41v 3198	. . . . . . . . . . . 12 ⊢ (∃𝑛 ∈ ( L ‘𝐶)(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ (∃𝑛 ∈ ( L ‘𝐶)ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)))
44	43	exbii 1881	. . . . . . . . . . 11 ⊢ (∃ℎ∃𝑛 ∈ ( L ‘𝐶)(ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃ℎ(∃𝑛 ∈ ( L ‘𝐶)ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)))
45	37, 42, 44	3bitr3ri 305	. . . . . . . . . 10 ⊢ (∃ℎ(∃𝑛 ∈ ( L ‘𝐶)ℎ = (𝐵 +s 𝑛) ∧ 𝑧 = (𝐴 +s ℎ)) ↔ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)))
46	36, 45	bitri 278	. . . . . . . . 9 ⊢ (∃ℎ ∈ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}𝑧 = (𝐴 +s ℎ) ↔ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)))
47	33, 46	orbi12i 928	. . . . . . . 8 ⊢ ((∃ℎ ∈ {𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)}𝑧 = (𝐴 +s ℎ) ∨ ∃ℎ ∈ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)}𝑧 = (𝐴 +s ℎ)) ↔ (∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)) ∨ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛))))
48	20, 47	bitri 278	. . . . . . 7 ⊢ (∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ) ↔ (∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)) ∨ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛))))
49	48	abbii 2833	. . . . . 6 ⊢ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)} = {𝑧 ∣ (∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)) ∨ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)))}
50		unab 4264	. . . . . 6 ⊢ ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛))}) = {𝑧 ∣ (∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶)) ∨ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)))}
51		eqeq1 2770	. . . . . . . . 9 ⊢ (𝑧 = 𝑤 → (𝑧 = (𝐴 +s (𝐵 +s 𝑛)) ↔ 𝑤 = (𝐴 +s (𝐵 +s 𝑛))))
52	51	rexbidv 3192	. . . . . . . 8 ⊢ (𝑧 = 𝑤 → (∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛)) ↔ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))))
53	52	cbvabv 2836	. . . . . . 7 ⊢ {𝑧 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛))} = {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}
54	53	uneq2i 4122	. . . . . 6 ⊢ ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑧 = (𝐴 +s (𝐵 +s 𝑛))}) = ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))})
55	49, 50, 54	3eqtr2i 2795	. . . . 5 ⊢ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)} = ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))})
56	55	uneq2i 4122	. . . 4 ⊢ ({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)}) = ({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}))
57		unass 4128	. . . 4 ⊢ (({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))}) ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}) = ({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ ({𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))} ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}))
58	56, 57	eqtr4i 2792	. . 3 ⊢ ({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)}) = (({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))}) ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))})
59		rexun 4152	. . . . . . . 8 ⊢ (∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖) ↔ (∃𝑖 ∈ {𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)}𝑏 = (𝐴 +s 𝑖) ∨ ∃𝑖 ∈ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}𝑏 = (𝐴 +s 𝑖)))
60		eqeq1 2770	. . . . . . . . . . . 12 ⊢ (𝑓 = 𝑖 → (𝑓 = (𝑞 +s 𝐶) ↔ 𝑖 = (𝑞 +s 𝐶)))
61	60	rexbidv 3192	. . . . . . . . . . 11 ⊢ (𝑓 = 𝑖 → (∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶) ↔ ∃𝑞 ∈ ( R ‘𝐵)𝑖 = (𝑞 +s 𝐶)))
62	61	rexab 3661	. . . . . . . . . 10 ⊢ (∃𝑖 ∈ {𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)}𝑏 = (𝐴 +s 𝑖) ↔ ∃𝑖(∃𝑞 ∈ ( R ‘𝐵)𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)))
63		rexcom4 3295	. . . . . . . . . . 11 ⊢ (∃𝑞 ∈ ( R ‘𝐵)∃𝑖(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑖∃𝑞 ∈ ( R ‘𝐵)(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)))
64		ovex 7456	. . . . . . . . . . . . 13 ⊢ (𝑞 +s 𝐶) ∈ V
65		oveq2 7431	. . . . . . . . . . . . . 14 ⊢ (𝑖 = (𝑞 +s 𝐶) → (𝐴 +s 𝑖) = (𝐴 +s (𝑞 +s 𝐶)))
66	65	eqeq2d 2777	. . . . . . . . . . . . 13 ⊢ (𝑖 = (𝑞 +s 𝐶) → (𝑏 = (𝐴 +s 𝑖) ↔ 𝑏 = (𝐴 +s (𝑞 +s 𝐶))))
67	64, 66	ceqsexv 3506	. . . . . . . . . . . 12 ⊢ (∃𝑖(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ 𝑏 = (𝐴 +s (𝑞 +s 𝐶)))
68	67	rexbii 3115	. . . . . . . . . . 11 ⊢ (∃𝑞 ∈ ( R ‘𝐵)∃𝑖(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)))
69		r19.41v 3198	. . . . . . . . . . . 12 ⊢ (∃𝑞 ∈ ( R ‘𝐵)(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ (∃𝑞 ∈ ( R ‘𝐵)𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)))
70	69	exbii 1881	. . . . . . . . . . 11 ⊢ (∃𝑖∃𝑞 ∈ ( R ‘𝐵)(𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑖(∃𝑞 ∈ ( R ‘𝐵)𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)))
71	63, 68, 70	3bitr3ri 305	. . . . . . . . . 10 ⊢ (∃𝑖(∃𝑞 ∈ ( R ‘𝐵)𝑖 = (𝑞 +s 𝐶) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)))
72	62, 71	bitri 278	. . . . . . . . 9 ⊢ (∃𝑖 ∈ {𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)}𝑏 = (𝐴 +s 𝑖) ↔ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)))
73		eqeq1 2770	. . . . . . . . . . . 12 ⊢ (𝑔 = 𝑖 → (𝑔 = (𝐵 +s 𝑟) ↔ 𝑖 = (𝐵 +s 𝑟)))
74	73	rexbidv 3192	. . . . . . . . . . 11 ⊢ (𝑔 = 𝑖 → (∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟) ↔ ∃𝑟 ∈ ( R ‘𝐶)𝑖 = (𝐵 +s 𝑟)))
75	74	rexab 3661	. . . . . . . . . 10 ⊢ (∃𝑖 ∈ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}𝑏 = (𝐴 +s 𝑖) ↔ ∃𝑖(∃𝑟 ∈ ( R ‘𝐶)𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)))
76		rexcom4 3295	. . . . . . . . . . 11 ⊢ (∃𝑟 ∈ ( R ‘𝐶)∃𝑖(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑖∃𝑟 ∈ ( R ‘𝐶)(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)))
77		ovex 7456	. . . . . . . . . . . . 13 ⊢ (𝐵 +s 𝑟) ∈ V
78		oveq2 7431	. . . . . . . . . . . . . 14 ⊢ (𝑖 = (𝐵 +s 𝑟) → (𝐴 +s 𝑖) = (𝐴 +s (𝐵 +s 𝑟)))
79	78	eqeq2d 2777	. . . . . . . . . . . . 13 ⊢ (𝑖 = (𝐵 +s 𝑟) → (𝑏 = (𝐴 +s 𝑖) ↔ 𝑏 = (𝐴 +s (𝐵 +s 𝑟))))
80	77, 79	ceqsexv 3506	. . . . . . . . . . . 12 ⊢ (∃𝑖(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ 𝑏 = (𝐴 +s (𝐵 +s 𝑟)))
81	80	rexbii 3115	. . . . . . . . . . 11 ⊢ (∃𝑟 ∈ ( R ‘𝐶)∃𝑖(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)))
82		r19.41v 3198	. . . . . . . . . . . 12 ⊢ (∃𝑟 ∈ ( R ‘𝐶)(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ (∃𝑟 ∈ ( R ‘𝐶)𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)))
83	82	exbii 1881	. . . . . . . . . . 11 ⊢ (∃𝑖∃𝑟 ∈ ( R ‘𝐶)(𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑖(∃𝑟 ∈ ( R ‘𝐶)𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)))
84	76, 81, 83	3bitr3ri 305	. . . . . . . . . 10 ⊢ (∃𝑖(∃𝑟 ∈ ( R ‘𝐶)𝑖 = (𝐵 +s 𝑟) ∧ 𝑏 = (𝐴 +s 𝑖)) ↔ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)))
85	75, 84	bitri 278	. . . . . . . . 9 ⊢ (∃𝑖 ∈ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}𝑏 = (𝐴 +s 𝑖) ↔ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)))
86	72, 85	orbi12i 928	. . . . . . . 8 ⊢ ((∃𝑖 ∈ {𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)}𝑏 = (𝐴 +s 𝑖) ∨ ∃𝑖 ∈ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)}𝑏 = (𝐴 +s 𝑖)) ↔ (∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)) ∨ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟))))
87	59, 86	bitri 278	. . . . . . 7 ⊢ (∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖) ↔ (∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)) ∨ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟))))
88	87	abbii 2833	. . . . . 6 ⊢ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)} = {𝑏 ∣ (∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)) ∨ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)))}
89		unab 4264	. . . . . 6 ⊢ ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟))}) = {𝑏 ∣ (∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶)) ∨ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)))}
90		eqeq1 2770	. . . . . . . . 9 ⊢ (𝑏 = 𝑐 → (𝑏 = (𝐴 +s (𝐵 +s 𝑟)) ↔ 𝑐 = (𝐴 +s (𝐵 +s 𝑟))))
91	90	rexbidv 3192	. . . . . . . 8 ⊢ (𝑏 = 𝑐 → (∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟)) ↔ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))))
92	91	cbvabv 2836	. . . . . . 7 ⊢ {𝑏 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟))} = {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))}
93	92	uneq2i 4122	. . . . . 6 ⊢ ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑏 = (𝐴 +s (𝐵 +s 𝑟))}) = ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))})
94	88, 89, 93	3eqtr2i 2795	. . . . 5 ⊢ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)} = ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))})
95	94	uneq2i 4122	. . . 4 ⊢ ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)}) = ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))}))
96		unass 4128	. . . 4 ⊢ (({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))}) ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))}) = ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ ({𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))} ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))}))
97	95, 96	eqtr4i 2792	. . 3 ⊢ ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)}) = (({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))}) ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))})
98	58, 97	oveq12i 7435	. 2 ⊢ (({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃ℎ ∈ ({𝑑 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑑 = (𝑚 +s 𝐶)} ∪ {𝑒 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑒 = (𝐵 +s 𝑛)})𝑧 = (𝐴 +s ℎ)}) |s ({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑖 ∈ ({𝑓 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑓 = (𝑞 +s 𝐶)} ∪ {𝑔 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑔 = (𝐵 +s 𝑟)})𝑏 = (𝐴 +s 𝑖)})) = ((({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))}) ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}) |s (({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))}) ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))}))
99	19, 98	eqtrdi 2817	1 ⊢ (𝜑 → (𝐴 +s (𝐵 +s 𝐶)) = ((({𝑦 ∣ ∃𝑙 ∈ ( L ‘𝐴)𝑦 = (𝑙 +s (𝐵 +s 𝐶))} ∪ {𝑧 ∣ ∃𝑚 ∈ ( L ‘𝐵)𝑧 = (𝐴 +s (𝑚 +s 𝐶))}) ∪ {𝑤 ∣ ∃𝑛 ∈ ( L ‘𝐶)𝑤 = (𝐴 +s (𝐵 +s 𝑛))}) |s (({𝑎 ∣ ∃𝑝 ∈ ( R ‘𝐴)𝑎 = (𝑝 +s (𝐵 +s 𝐶))} ∪ {𝑏 ∣ ∃𝑞 ∈ ( R ‘𝐵)𝑏 = (𝐴 +s (𝑞 +s 𝐶))}) ∪ {𝑐 ∣ ∃𝑟 ∈ ( R ‘𝐶)𝑐 = (𝐴 +s (𝐵 +s 𝑟))})))

This proof depends on syntax axioms:   → wi 4   ∧ wa 401   ∨ wo 861   = wceq 1570  ∃wex 1812   ∈ wcel 2146  {cab 2744   ≠ wne 2961  ∃wrex 3092   ∪ cun 3906  ∅c0 4289  {csn 4594   class class class wbr 5114  ‘cfv 6543  (class class class)co 7423   No csur 27841   <<s cslts 27987   |s ccuts 27989   L cleft 28055   R cright 28056   +_s cadds 28189

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-ext 2738  ax-rep 5243  ax-sep 5262  ax-nul 5274  ax-pow 5341  ax-pr 5409  ax-un 7745

This proof depends on definitions:  df-bi 210  df-an 402  df-or 862  df-3or 1104  df-3an 1105  df-tru 1573  df-fal 1583  df-ex 1813  df-nf 1817  df-sb 2100  df-mo 2570  df-eu 2600  df-clab 2745  df-cleq 2758  df-clel 2841  df-nfc 2915  df-ne 2962  df-ral 3083  df-rex 3093  df-rmo 3372  df-reu 3373  df-rab 3420  df-v 3460  df-sbc 3748  df-csb 3857  df-dif 3911  df-un 3913  df-in 3915  df-ss 3925  df-pss 3928  df-nul 4290  df-if 4493  df-pw 4569  df-sn 4595  df-pr 4597  df-tp 4599  df-op 4601  df-ot 4603  df-uni 4878  df-int 4918  df-iun 4963  df-br 5115  df-opab 5179  df-mpt 5198  df-tr 5224  df-id 5561  df-eprel 5566  df-po 5574  df-so 5575  df-fr 5619  df-se 5620  df-we 5621  df-xp 5672  df-rel 5673  df-cnv 5674  df-co 5675  df-dm 5676  df-rn 5677  df-res 5678  df-ima 5679  df-pred 6309  df-ord 6370  df-on 6371  df-suc 6373  df-iota 6499  df-fun 6545  df-fn 6546  df-f 6547  df-f1 6548  df-fo 6549  df-f1o 6550  df-fv 6551  df-riota 7380  df-ov 7426  df-oprab 7427  df-mpo 7428  df-1st 7995  df-2nd 7996  df-frecs 8287  df-wrecs 8318  df-recs 8367  df-1o 8462  df-2o 8463  df-nadd 8661  df-no 27844  df-lts 27845  df-bday 27846  df-les 27946  df-slts 27988  df-cuts 27990  df-0s 28037  df-made 28057  df-old 28058  df-left 28060  df-right 28061  df-norec2 28179  df-adds 28190

This theorem is used by:  addsass  28235