Theorem zseo 28838

Description: A surreal integer is either even or odd. (Contributed by Scott Fenton, 19-Aug-2025.)

Assertion

Ref	Expression
zseo	⊢ (𝑁 ∈ ℤs → (∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s )))

Distinct variable group:   𝑥,𝑁

Proof of Theorem zseo

Dummy variables 𝑦 𝑧 𝑤 𝑡 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		elzs 28800	. 2 ⊢ (𝑁 ∈ ℤs ↔ ∃𝑦 ∈ ℕs ∃𝑧 ∈ ℕs 𝑁 = (𝑦 −s 𝑧))
2		nnn0s 28743	. . . . . 6 ⊢ (𝑦 ∈ ℕs → 𝑦 ∈ ℕ0s)
3		n0seo 28837	. . . . . 6 ⊢ (𝑦 ∈ ℕ0s → (∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∨ ∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s )))
4	2, 3	syl 18	. . . . 5 ⊢ (𝑦 ∈ ℕs → (∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∨ ∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s )))
5		nnn0s 28743	. . . . . 6 ⊢ (𝑧 ∈ ℕs → 𝑧 ∈ ℕ0s)
6		n0seo 28837	. . . . . 6 ⊢ (𝑧 ∈ ℕ0s → (∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡) ∨ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )))
7	5, 6	syl 18	. . . . 5 ⊢ (𝑧 ∈ ℕs → (∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡) ∨ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )))
8		reeanv 3238	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) ↔ (∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)))
9		n0zs 28805	. . . . . . . . . . . . 13 ⊢ (𝑤 ∈ ℕ0s → 𝑤 ∈ ℤs)
10	9	adantr 486	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 𝑤 ∈ ℤs)
11		n0zs 28805	. . . . . . . . . . . . 13 ⊢ (𝑡 ∈ ℕ0s → 𝑡 ∈ ℤs)
12	11	adantl 487	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 𝑡 ∈ ℤs)
13	10, 12	zsubscld 28812	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (𝑤 −s 𝑡) ∈ ℤs)
14		2no 28835	. . . . . . . . . . . . . 14 ⊢ 2s ∈ No
15	14	a1i 11	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 2s ∈ No)
16		n0no 28739	. . . . . . . . . . . . . 14 ⊢ (𝑤 ∈ ℕ0s → 𝑤 ∈ No)
17	16	adantr 486	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 𝑤 ∈ No)
18		n0no 28739	. . . . . . . . . . . . . 14 ⊢ (𝑡 ∈ ℕ0s → 𝑡 ∈ No)
19	18	adantl 487	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 𝑡 ∈ No)
20	15, 17, 19	subsdid 28574	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (2s ·s (𝑤 −s 𝑡)) = ((2s ·s 𝑤) −s (2s ·s 𝑡)))
21	20	eqcomd 2769	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s (𝑤 −s 𝑡)))
22		oveq2 7451	. . . . . . . . . . . 12 ⊢ (𝑥 = (𝑤 −s 𝑡) → (2s ·s 𝑥) = (2s ·s (𝑤 −s 𝑡)))
23	22	rspceeqv 3602	. . . . . . . . . . 11 ⊢ (((𝑤 −s 𝑡) ∈ ℤs ∧ ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s (𝑤 −s 𝑡))) → ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s 𝑥))
24	13, 21, 23	syl2anc 596	. . . . . . . . . 10 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s 𝑥))
25		oveq12 7452	. . . . . . . . . . . 12 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) → (𝑦 −s 𝑧) = ((2s ·s 𝑤) −s (2s ·s 𝑡)))
26	25	eqeq1d 2765	. . . . . . . . . . 11 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) → ((𝑦 −s 𝑧) = (2s ·s 𝑥) ↔ ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s 𝑥)))
27	26	rexbidv 3190	. . . . . . . . . 10 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ↔ ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s (2s ·s 𝑡)) = (2s ·s 𝑥)))
28	24, 27	syl5ibrcom 250	. . . . . . . . 9 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥)))
29	28	rexlimivv 3208	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = (2s ·s 𝑤) ∧ 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥))
30	8, 29	sylbir 238	. . . . . . 7 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥))
31	30	orcd 887	. . . . . 6 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
32		reeanv 3238	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) ↔ (∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)))
33	15, 17	mulscld 28551	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (2s ·s 𝑤) ∈ No)
34		1no 28226	. . . . . . . . . . . . . 14 ⊢ 1s ∈ No
35	34	a1i 11	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 1s ∈ No)
36	15, 19	mulscld 28551	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (2s ·s 𝑡) ∈ No)
37	33, 35, 36	addsubsd 28498	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s 1s ))
38	21	oveq1d 7458	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s 1s ))
39	37, 38	eqtrd 2798	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s (𝑤 −s 𝑡)) +s 1s ))
40	22	oveq1d 7458	. . . . . . . . . . . 12 ⊢ (𝑥 = (𝑤 −s 𝑡) → ((2s ·s 𝑥) +s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s 1s ))
41	40	rspceeqv 3602	. . . . . . . . . . 11 ⊢ (((𝑤 −s 𝑡) ∈ ℤs ∧ (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s (𝑤 −s 𝑡)) +s 1s )) → ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s 𝑥) +s 1s ))
42	13, 39, 41	syl2anc 596	. . . . . . . . . 10 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s 𝑥) +s 1s ))
43		oveq12 7452	. . . . . . . . . . . 12 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) → (𝑦 −s 𝑧) = (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)))
44	43	eqeq1d 2765	. . . . . . . . . . 11 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) → ((𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ) ↔ (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s 𝑥) +s 1s )))
45	44	rexbidv 3190	. . . . . . . . . 10 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ) ↔ ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s (2s ·s 𝑡)) = ((2s ·s 𝑥) +s 1s )))
46	42, 45	syl5ibrcom 250	. . . . . . . . 9 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
47	46	rexlimivv 3208	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ))
48	32, 47	sylbir 238	. . . . . . 7 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ))
49	48	olcd 888	. . . . . 6 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡)) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
50		reeanv 3238	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) ↔ (∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )))
51		1zs 28807	. . . . . . . . . . . . 13 ⊢ 1s ∈ ℤs
52	51	a1i 11	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → 1s ∈ ℤs)
53	13, 52	zsubscld 28812	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((𝑤 −s 𝑡) −s 1s ) ∈ ℤs)
54	13	znod 28799	. . . . . . . . . . . . . . 15 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (𝑤 −s 𝑡) ∈ No)
55	15, 54, 35	subsdid 28574	. . . . . . . . . . . . . 14 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (2s ·s ((𝑤 −s 𝑡) −s 1s )) = ((2s ·s (𝑤 −s 𝑡)) −s (2s ·s 1s )))
56	55	oveq1d 7458	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s ((𝑤 −s 𝑡) −s 1s )) +s 1s ) = (((2s ·s (𝑤 −s 𝑡)) −s (2s ·s 1s )) +s 1s ))
57		mulsrid 28529	. . . . . . . . . . . . . . . . 17 ⊢ (2s ∈ No → (2s ·s 1s ) = 2s)
58	14, 57	ax-mp 5	. . . . . . . . . . . . . . . 16 ⊢ (2s ·s 1s ) = 2s
59	58	oveq2i 7454	. . . . . . . . . . . . . . 15 ⊢ ((2s ·s (𝑤 −s 𝑡)) −s (2s ·s 1s )) = ((2s ·s (𝑤 −s 𝑡)) −s 2s)
60	59	oveq1i 7453	. . . . . . . . . . . . . 14 ⊢ (((2s ·s (𝑤 −s 𝑡)) −s (2s ·s 1s )) +s 1s ) = (((2s ·s (𝑤 −s 𝑡)) −s 2s) +s 1s )
61	15, 54	mulscld 28551	. . . . . . . . . . . . . . . 16 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (2s ·s (𝑤 −s 𝑡)) ∈ No)
62	61, 35, 15	addsubsd 28498	. . . . . . . . . . . . . . 15 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s (𝑤 −s 𝑡)) +s 1s ) −s 2s) = (((2s ·s (𝑤 −s 𝑡)) −s 2s) +s 1s ))
63	61, 35, 15	addsubsassd 28497	. . . . . . . . . . . . . . 15 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s (𝑤 −s 𝑡)) +s 1s ) −s 2s) = ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)))
64	62, 63	eqtr3d 2800	. . . . . . . . . . . . . 14 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s (𝑤 −s 𝑡)) −s 2s) +s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)))
65	60, 64	eqtrid 2810	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s (𝑤 −s 𝑡)) −s (2s ·s 1s )) +s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)))
66	56, 65	eqtrd 2798	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s ((𝑤 −s 𝑡) −s 1s )) +s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)))
67		subscl 28478	. . . . . . . . . . . . . . . . . 18 ⊢ (( 1s ∈ No ∧ 2s ∈ No) → ( 1s −s 2s) ∈ No)
68	34, 14, 67	mp2an 705	. . . . . . . . . . . . . . . . 17 ⊢ ( 1s −s 2s) ∈ No
69		negnegs 28460	. . . . . . . . . . . . . . . . 17 ⊢ (( 1s −s 2s) ∈ No → ( -s‘( -s‘( 1s −s 2s))) = ( 1s −s 2s))
70	68, 69	ax-mp 5	. . . . . . . . . . . . . . . 16 ⊢ ( -s‘( -s‘( 1s −s 2s))) = ( 1s −s 2s)
71	34	a1i 11	. . . . . . . . . . . . . . . . . . . 20 ⊢ (⊤ → 1s ∈ No)
72	14	a1i 11	. . . . . . . . . . . . . . . . . . . 20 ⊢ (⊤ → 2s ∈ No)
73	71, 72	negsubsdi2d 28496	. . . . . . . . . . . . . . . . . . 19 ⊢ (⊤ → ( -s‘( 1s −s 2s)) = (2s −s 1s ))
74	73	mptru 1577	. . . . . . . . . . . . . . . . . 18 ⊢ ( -s‘( 1s −s 2s)) = (2s −s 1s )
75		1p1e2s 28832	. . . . . . . . . . . . . . . . . . 19 ⊢ ( 1s +s 1s ) = 2s
76		subadds 28486	. . . . . . . . . . . . . . . . . . . 20 ⊢ ((2s ∈ No ∧ 1s ∈ No ∧ 1s ∈ No) → ((2s −s 1s ) = 1s ↔ ( 1s +s 1s ) = 2s))
77	14, 34, 34, 76	mp3an 1491	. . . . . . . . . . . . . . . . . . 19 ⊢ ((2s −s 1s ) = 1s ↔ ( 1s +s 1s ) = 2s)
78	75, 77	mpbir 234	. . . . . . . . . . . . . . . . . 18 ⊢ (2s −s 1s ) = 1s
79	74, 78	eqtri 2786	. . . . . . . . . . . . . . . . 17 ⊢ ( -s‘( 1s −s 2s)) = 1s
80	79	fveq2i 6911	. . . . . . . . . . . . . . . 16 ⊢ ( -s‘( -s‘( 1s −s 2s))) = ( -s‘ 1s )
81	70, 80	eqtr3i 2788	. . . . . . . . . . . . . . 15 ⊢ ( 1s −s 2s) = ( -s‘ 1s )
82	81	oveq2i 7454	. . . . . . . . . . . . . 14 ⊢ ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)) = ((2s ·s (𝑤 −s 𝑡)) +s ( -s‘ 1s ))
83	61, 35	subsvald 28477	. . . . . . . . . . . . . 14 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s (𝑤 −s 𝑡)) −s 1s ) = ((2s ·s (𝑤 −s 𝑡)) +s ( -s‘ 1s )))
84	82, 83	eqtr4id 2817	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)) = ((2s ·s (𝑤 −s 𝑡)) −s 1s ))
85	20	oveq1d 7458	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s (𝑤 −s 𝑡)) −s 1s ) = (((2s ·s 𝑤) −s (2s ·s 𝑡)) −s 1s ))
86	84, 85	eqtrd 2798	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s (𝑤 −s 𝑡)) +s ( 1s −s 2s)) = (((2s ·s 𝑤) −s (2s ·s 𝑡)) −s 1s ))
87	33, 36, 35	subsubs4d 28510	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) −s (2s ·s 𝑡)) −s 1s ) = ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )))
88	66, 86, 87	3eqtrrd 2803	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s ((𝑤 −s 𝑡) −s 1s )) +s 1s ))
89		oveq2 7451	. . . . . . . . . . . . 13 ⊢ (𝑥 = ((𝑤 −s 𝑡) −s 1s ) → (2s ·s 𝑥) = (2s ·s ((𝑤 −s 𝑡) −s 1s )))
90	89	oveq1d 7458	. . . . . . . . . . . 12 ⊢ (𝑥 = ((𝑤 −s 𝑡) −s 1s ) → ((2s ·s 𝑥) +s 1s ) = ((2s ·s ((𝑤 −s 𝑡) −s 1s )) +s 1s ))
91	90	rspceeqv 3602	. . . . . . . . . . 11 ⊢ ((((𝑤 −s 𝑡) −s 1s ) ∈ ℤs ∧ ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s ((𝑤 −s 𝑡) −s 1s )) +s 1s )) → ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s 𝑥) +s 1s ))
92	53, 88, 91	syl2anc 596	. . . . . . . . . 10 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s 𝑥) +s 1s ))
93		oveq12 7452	. . . . . . . . . . . 12 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → (𝑦 −s 𝑧) = ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )))
94	93	eqeq1d 2765	. . . . . . . . . . 11 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ((𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ) ↔ ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s 𝑥) +s 1s )))
95	94	rexbidv 3190	. . . . . . . . . 10 ⊢ ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ) ↔ ∃𝑥 ∈ ℤs ((2s ·s 𝑤) −s ((2s ·s 𝑡) +s 1s )) = ((2s ·s 𝑥) +s 1s )))
96	92, 95	syl5ibrcom 250	. . . . . . . . 9 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
97	96	rexlimivv 3208	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = (2s ·s 𝑤) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ))
98	50, 97	sylbir 238	. . . . . . 7 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ))
99	98	olcd 888	. . . . . 6 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
100		reeanv 3238	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) ↔ (∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )))
101	33, 35, 36, 35	addsubs4d 28517	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s ( 1s −s 1s )))
102		subsid 28485	. . . . . . . . . . . . . . 15 ⊢ ( 1s ∈ No → ( 1s −s 1s ) = 0s )
103	34, 102	ax-mp 5	. . . . . . . . . . . . . 14 ⊢ ( 1s −s 1s ) = 0s
104	103	oveq2i 7454	. . . . . . . . . . . . 13 ⊢ (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s ( 1s −s 1s )) = (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s 0s )
105	33, 36	subscld 28479	. . . . . . . . . . . . . . 15 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((2s ·s 𝑤) −s (2s ·s 𝑡)) ∈ No)
106	105	addsridd 28381	. . . . . . . . . . . . . 14 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s 0s ) = ((2s ·s 𝑤) −s (2s ·s 𝑡)))
107	106, 21	eqtrd 2798	. . . . . . . . . . . . 13 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s 0s ) = (2s ·s (𝑤 −s 𝑡)))
108	104, 107	eqtrid 2810	. . . . . . . . . . . 12 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) −s (2s ·s 𝑡)) +s ( 1s −s 1s )) = (2s ·s (𝑤 −s 𝑡)))
109	101, 108	eqtrd 2798	. . . . . . . . . . 11 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s (𝑤 −s 𝑡)))
110	22	rspceeqv 3602	. . . . . . . . . . 11 ⊢ (((𝑤 −s 𝑡) ∈ ℤs ∧ (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s (𝑤 −s 𝑡))) → ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s 𝑥))
111	13, 109, 110	syl2anc 596	. . . . . . . . . 10 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s 𝑥))
112		oveq12 7452	. . . . . . . . . . . 12 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → (𝑦 −s 𝑧) = (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )))
113	112	eqeq1d 2765	. . . . . . . . . . 11 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ((𝑦 −s 𝑧) = (2s ·s 𝑥) ↔ (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s 𝑥)))
114	113	rexbidv 3190	. . . . . . . . . 10 ⊢ ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ↔ ∃𝑥 ∈ ℤs (((2s ·s 𝑤) +s 1s ) −s ((2s ·s 𝑡) +s 1s )) = (2s ·s 𝑥)))
115	111, 114	syl5ibrcom 250	. . . . . . . . 9 ⊢ ((𝑤 ∈ ℕ0s ∧ 𝑡 ∈ ℕ0s) → ((𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥)))
116	115	rexlimivv 3208	. . . . . . . 8 ⊢ (∃𝑤 ∈ ℕ0s ∃𝑡 ∈ ℕ0s (𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥))
117	100, 116	sylbir 238	. . . . . . 7 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )) → ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥))
118	117	orcd 887	. . . . . 6 ⊢ ((∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s ) ∧ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s )) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
119	31, 49, 99, 118	ccase 1053	. . . . 5 ⊢ (((∃𝑤 ∈ ℕ0s 𝑦 = (2s ·s 𝑤) ∨ ∃𝑤 ∈ ℕ0s 𝑦 = ((2s ·s 𝑤) +s 1s )) ∧ (∃𝑡 ∈ ℕ0s 𝑧 = (2s ·s 𝑡) ∨ ∃𝑡 ∈ ℕ0s 𝑧 = ((2s ·s 𝑡) +s 1s ))) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
120	4, 7, 119	syl2an 608	. . . 4 ⊢ ((𝑦 ∈ ℕs ∧ 𝑧 ∈ ℕs) → (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
121		eqeq1 2767	. . . . . 6 ⊢ (𝑁 = (𝑦 −s 𝑧) → (𝑁 = (2s ·s 𝑥) ↔ (𝑦 −s 𝑧) = (2s ·s 𝑥)))
122	121	rexbidv 3190	. . . . 5 ⊢ (𝑁 = (𝑦 −s 𝑧) → (∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ↔ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥)))
123		eqeq1 2767	. . . . . 6 ⊢ (𝑁 = (𝑦 −s 𝑧) → (𝑁 = ((2s ·s 𝑥) +s 1s ) ↔ (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
124	123	rexbidv 3190	. . . . 5 ⊢ (𝑁 = (𝑦 −s 𝑧) → (∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s ) ↔ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s )))
125	122, 124	orbi12d 932	. . . 4 ⊢ (𝑁 = (𝑦 −s 𝑧) → ((∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s )) ↔ (∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs (𝑦 −s 𝑧) = ((2s ·s 𝑥) +s 1s ))))
126	120, 125	syl5ibrcom 250	. . 3 ⊢ ((𝑦 ∈ ℕs ∧ 𝑧 ∈ ℕs) → (𝑁 = (𝑦 −s 𝑧) → (∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s ))))
127	126	rexlimivv 3208	. 2 ⊢ (∃𝑦 ∈ ℕs ∃𝑧 ∈ ℕs 𝑁 = (𝑦 −s 𝑧) → (∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s )))
128	1, 127	sylbi 220	1 ⊢ (𝑁 ∈ ℤs → (∃𝑥 ∈ ℤs 𝑁 = (2s ·s 𝑥) ∨ ∃𝑥 ∈ ℤs 𝑁 = ((2s ·s 𝑥) +s 1s )))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∧ wa 401   ∨ wo 861   = wceq 1570  ⊤wtru 1571   ∈ wcel 2147  ∃wrex 3090  ‘cfv 6558  (class class class)co 7443  Nocsur 28027   0_s c0s 28221   1_s c1s 28222   +_s cadds 28375   -_scnegs 28435   −_s csubs 28436   ·_s cmuls 28522  ℕ_0scn0s 28728  ℕ_scnns 28729  ℤ_sczs 28794  2_sc2s 28826

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 1945  ax-6 2002  ax-7 2043  ax-8 2149  ax-9 2157  ax-10 2180  ax-11 2197  ax-12 2216  ax-ext 2735  ax-rep 5235  ax-sep 5252  ax-nul 5263  ax-pow 5331  ax-pr 5395  ax-un 7775

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 2102  df-mo 2567  df-eu 2597  df-clab 2742  df-cleq 2755  df-clel 2839  df-nfc 2913  df-ne 2960  df-ral 3081  df-rex 3091  df-rmo 3369  df-reu 3370  df-rab 3417  df-v 3456  df-sbc 3743  df-csb 3852  df-ss 3901  df-pss 4017  df-dif 4050  df-in 4094  df-un 4154  df-nul 4282  df-if 4486  df-pw 4562  df-sn 4589  df-pr 4591  df-tp 4593  df-op 4839  df-ot 4862  df-uni 4871  df-int 4911  df-iun 4956  df-br 5107  df-opab 5171  df-mpt 5190  df-tr 5216  df-id 5550  df-eprel 5555  df-po 5563  df-so 5564  df-fr 5608  df-se 5609  df-we 5610  df-xp 5661  df-rel 5662  df-cnv 5663  df-co 5664  df-dm 5665  df-rn 5666  df-res 5667  df-ima 5668  df-pred 6322  df-ord 6383  df-on 6384  df-lim 6385  df-suc 6386  df-iota 6512  df-fun 6560  df-fn 6561  df-f 6562  df-f1 6563  df-fo 6564  df-f1o 6565  df-fv 6566  df-riota 7400  df-ov 7446  df-oprab 7447  df-mpo 7448  df-om 7902  df-1st 8025  df-2nd 8026  df-frecs 8327  df-wrecs 8358  df-recs 8407  df-rdg 8446  df-1o 8504  df-2o 8505  df-nadd 8703  df-no 28030  df-lts 28031  df-bday 28032  df-les 28132  df-slts 28174  df-cuts 28176  df-0s 28223  df-1s 28224  df-made 28243  df-old 28244  df-left 28246  df-right 28247  df-norec 28354  df-norec2 28365  df-adds 28376  df-negs 28437  df-subs 28438  df-muls 28523  df-n0s 28730  df-nns 28731  df-zs 28795  df-2s 28827

This theorem is used by:  z12zsodd  28898