Theorem prod1dc 11732

Description: Any product of one over a valid set is one. (Contributed by Scott Fenton, 7-Dec-2017.) (Revised by Jim Kingdon, 5-Aug-2024.)

Assertion

Ref	Expression
prod1dc	⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∨ 𝐴 ∈ Fin) → ∏𝑘 ∈ 𝐴 1 = 1)

Distinct variable groups:   𝐴,𝑗,𝑘   𝑗,𝑀,𝑘

Proof of Theorem prod1dc

Dummy variables 𝑎 𝑓 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		eqid 2193	. . 3 ⊢ (ℤ≥‘𝑀) = (ℤ≥‘𝑀)
2		simp1 999	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → 𝑀 ∈ ℤ)
3		1ap0 8611	. . . 4 ⊢ 1 # 0
4	3	a1i 9	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → 1 # 0)
5	1	prodfclim1 11690	. . . 4 ⊢ (𝑀 ∈ ℤ → seq𝑀( · , ((ℤ≥‘𝑀) × {1})) ⇝ 1)
6	2, 5	syl 14	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → seq𝑀( · , ((ℤ≥‘𝑀) × {1})) ⇝ 1)
7		simp3 1001	. . . 4 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴)
8		eleq1w 2254	. . . . . 6 ⊢ (𝑗 = 𝑎 → (𝑗 ∈ 𝐴 ↔ 𝑎 ∈ 𝐴))
9	8	dcbid 839	. . . . 5 ⊢ (𝑗 = 𝑎 → (DECID 𝑗 ∈ 𝐴 ↔ DECID 𝑎 ∈ 𝐴))
10	9	cbvralv 2726	. . . 4 ⊢ (∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴 ↔ ∀𝑎 ∈ (ℤ≥‘𝑀)DECID 𝑎 ∈ 𝐴)
11	7, 10	sylib 122	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ∀𝑎 ∈ (ℤ≥‘𝑀)DECID 𝑎 ∈ 𝐴)
12		simp2 1000	. . 3 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → 𝐴 ⊆ (ℤ≥‘𝑀))
13		1ex 8016	. . . . . 6 ⊢ 1 ∈ V
14	13	fvconst2 5775	. . . . 5 ⊢ (𝑘 ∈ (ℤ≥‘𝑀) → (((ℤ≥‘𝑀) × {1})‘𝑘) = 1)
15	14	adantl 277	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → (((ℤ≥‘𝑀) × {1})‘𝑘) = 1)
16		eleq1w 2254	. . . . . . 7 ⊢ (𝑎 = 𝑘 → (𝑎 ∈ 𝐴 ↔ 𝑘 ∈ 𝐴))
17	16	dcbid 839	. . . . . 6 ⊢ (𝑎 = 𝑘 → (DECID 𝑎 ∈ 𝐴 ↔ DECID 𝑘 ∈ 𝐴))
18	11	adantr 276	. . . . . 6 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → ∀𝑎 ∈ (ℤ≥‘𝑀)DECID 𝑎 ∈ 𝐴)
19		simpr 110	. . . . . 6 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → 𝑘 ∈ (ℤ≥‘𝑀))
20	17, 18, 19	rspcdva 2870	. . . . 5 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → DECID 𝑘 ∈ 𝐴)
21		ifiddc 3592	. . . . 5 ⊢ (DECID 𝑘 ∈ 𝐴 → if(𝑘 ∈ 𝐴, 1, 1) = 1)
22	20, 21	syl 14	. . . 4 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → if(𝑘 ∈ 𝐴, 1, 1) = 1)
23	15, 22	eqtr4d 2229	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ (ℤ≥‘𝑀)) → (((ℤ≥‘𝑀) × {1})‘𝑘) = if(𝑘 ∈ 𝐴, 1, 1))
24		1cnd 8037	. . 3 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∧ 𝑘 ∈ 𝐴) → 1 ∈ ℂ)
25	1, 2, 4, 6, 11, 12, 23, 24	zprodap0 11727	. 2 ⊢ ((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) → ∏𝑘 ∈ 𝐴 1 = 1)
26		fz1f1o 11521	. . 3 ⊢ (𝐴 ∈ Fin → (𝐴 = ∅ ∨ ((♯‘𝐴) ∈ ℕ ∧ ∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)))
27		prodeq1 11699	. . . . 5 ⊢ (𝐴 = ∅ → ∏𝑘 ∈ 𝐴 1 = ∏𝑘 ∈ ∅ 1)
28		prod0 11731	. . . . 5 ⊢ ∏𝑘 ∈ ∅ 1 = 1
29	27, 28	eqtrdi 2242	. . . 4 ⊢ (𝐴 = ∅ → ∏𝑘 ∈ 𝐴 1 = 1)
30		eqidd 2194	. . . . . . . . . 10 ⊢ (𝑘 = (𝑓‘𝑗) → 1 = 1)
31		simpl 109	. . . . . . . . . 10 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (♯‘𝐴) ∈ ℕ)
32		simpr 110	. . . . . . . . . 10 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)
33		1cnd 8037	. . . . . . . . . 10 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) ∧ 𝑘 ∈ 𝐴) → 1 ∈ ℂ)
34		elfznn 10123	. . . . . . . . . . . 12 ⊢ (𝑗 ∈ (1...(♯‘𝐴)) → 𝑗 ∈ ℕ)
35	13	fvconst2 5775	. . . . . . . . . . . 12 ⊢ (𝑗 ∈ ℕ → ((ℕ × {1})‘𝑗) = 1)
36	34, 35	syl 14	. . . . . . . . . . 11 ⊢ (𝑗 ∈ (1...(♯‘𝐴)) → ((ℕ × {1})‘𝑗) = 1)
37	36	adantl 277	. . . . . . . . . 10 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) ∧ 𝑗 ∈ (1...(♯‘𝐴))) → ((ℕ × {1})‘𝑗) = 1)
38	30, 31, 32, 33, 37	fprodseq 11729	. . . . . . . . 9 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → ∏𝑘 ∈ 𝐴 1 = (seq1( · , (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1)))‘(♯‘𝐴)))
39		simpr 110	. . . . . . . . . . . . . . . . 17 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ 𝑗 ≤ (♯‘𝐴)) → 𝑗 ≤ (♯‘𝐴))
40	39	iftrued 3565	. . . . . . . . . . . . . . . 16 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ 𝑗 ≤ (♯‘𝐴)) → if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1) = ((ℕ × {1})‘𝑗))
41	35	ad2antlr 489	. . . . . . . . . . . . . . . 16 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ 𝑗 ≤ (♯‘𝐴)) → ((ℕ × {1})‘𝑗) = 1)
42	40, 41	eqtrd 2226	. . . . . . . . . . . . . . 15 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ 𝑗 ≤ (♯‘𝐴)) → if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1) = 1)
43		simpr 110	. . . . . . . . . . . . . . . 16 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ ¬ 𝑗 ≤ (♯‘𝐴)) → ¬ 𝑗 ≤ (♯‘𝐴))
44	43	iffalsed 3568	. . . . . . . . . . . . . . 15 ⊢ ((((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) ∧ ¬ 𝑗 ≤ (♯‘𝐴)) → if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1) = 1)
45		nnz 9339	. . . . . . . . . . . . . . . . 17 ⊢ (𝑗 ∈ ℕ → 𝑗 ∈ ℤ)
46		nnz 9339	. . . . . . . . . . . . . . . . 17 ⊢ ((♯‘𝐴) ∈ ℕ → (♯‘𝐴) ∈ ℤ)
47		zdcle 9396	. . . . . . . . . . . . . . . . 17 ⊢ ((𝑗 ∈ ℤ ∧ (♯‘𝐴) ∈ ℤ) → DECID 𝑗 ≤ (♯‘𝐴))
48	45, 46, 47	syl2anr 290	. . . . . . . . . . . . . . . 16 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) → DECID 𝑗 ≤ (♯‘𝐴))
49		exmiddc 837	. . . . . . . . . . . . . . . 16 ⊢ (DECID 𝑗 ≤ (♯‘𝐴) → (𝑗 ≤ (♯‘𝐴) ∨ ¬ 𝑗 ≤ (♯‘𝐴)))
50	48, 49	syl 14	. . . . . . . . . . . . . . 15 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) → (𝑗 ≤ (♯‘𝐴) ∨ ¬ 𝑗 ≤ (♯‘𝐴)))
51	42, 44, 50	mpjaodan 799	. . . . . . . . . . . . . 14 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑗 ∈ ℕ) → if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1) = 1)
52	51	mpteq2dva 4120	. . . . . . . . . . . . 13 ⊢ ((♯‘𝐴) ∈ ℕ → (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1)) = (𝑗 ∈ ℕ ↦ 1))
53		fconstmpt 4707	. . . . . . . . . . . . 13 ⊢ (ℕ × {1}) = (𝑗 ∈ ℕ ↦ 1)
54	52, 53	eqtr4di 2244	. . . . . . . . . . . 12 ⊢ ((♯‘𝐴) ∈ ℕ → (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1)) = (ℕ × {1}))
55	54	seqeq3d 10529	. . . . . . . . . . 11 ⊢ ((♯‘𝐴) ∈ ℕ → seq1( · , (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1))) = seq1( · , (ℕ × {1})))
56	55	adantr 276	. . . . . . . . . 10 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → seq1( · , (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1))) = seq1( · , (ℕ × {1})))
57	56	fveq1d 5557	. . . . . . . . 9 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (seq1( · , (𝑗 ∈ ℕ ↦ if(𝑗 ≤ (♯‘𝐴), ((ℕ × {1})‘𝑗), 1)))‘(♯‘𝐴)) = (seq1( · , (ℕ × {1}))‘(♯‘𝐴)))
58	38, 57	eqtrd 2226	. . . . . . . 8 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → ∏𝑘 ∈ 𝐴 1 = (seq1( · , (ℕ × {1}))‘(♯‘𝐴)))
59		nnuz 9631	. . . . . . . . . 10 ⊢ ℕ = (ℤ≥‘1)
60	59	prodf1 11688	. . . . . . . . 9 ⊢ ((♯‘𝐴) ∈ ℕ → (seq1( · , (ℕ × {1}))‘(♯‘𝐴)) = 1)
61	60	adantr 276	. . . . . . . 8 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → (seq1( · , (ℕ × {1}))‘(♯‘𝐴)) = 1)
62	58, 61	eqtrd 2226	. . . . . . 7 ⊢ (((♯‘𝐴) ∈ ℕ ∧ 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → ∏𝑘 ∈ 𝐴 1 = 1)
63	62	ex 115	. . . . . 6 ⊢ ((♯‘𝐴) ∈ ℕ → (𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → ∏𝑘 ∈ 𝐴 1 = 1))
64	63	exlimdv 1830	. . . . 5 ⊢ ((♯‘𝐴) ∈ ℕ → (∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴 → ∏𝑘 ∈ 𝐴 1 = 1))
65	64	imp 124	. . . 4 ⊢ (((♯‘𝐴) ∈ ℕ ∧ ∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴) → ∏𝑘 ∈ 𝐴 1 = 1)
66	29, 65	jaoi 717	. . 3 ⊢ ((𝐴 = ∅ ∨ ((♯‘𝐴) ∈ ℕ ∧ ∃𝑓 𝑓:(1...(♯‘𝐴))–1-1-onto→𝐴)) → ∏𝑘 ∈ 𝐴 1 = 1)
67	26, 66	syl 14	. 2 ⊢ (𝐴 ∈ Fin → ∏𝑘 ∈ 𝐴 1 = 1)
68	25, 67	jaoi 717	1 ⊢ (((𝑀 ∈ ℤ ∧ 𝐴 ⊆ (ℤ≥‘𝑀) ∧ ∀𝑗 ∈ (ℤ≥‘𝑀)DECID 𝑗 ∈ 𝐴) ∨ 𝐴 ∈ Fin) → ∏𝑘 ∈ 𝐴 1 = 1)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 104   ∨ wo 709  DECID wdc 835   ∧ w3a 980   = wceq 1364  ∃wex 1503   ∈ wcel 2164  ∀wral 2472   ⊆ wss 3154  ∅c0 3447  ifcif 3558  {csn 3619   class class class wbr 4030   ↦ cmpt 4091   × cxp 4658  –1-1-onto→wf1o 5254  ‘cfv 5255  (class class class)co 5919  Fincfn 6796  0cc0 7874  1c1 7875   · cmul 7879   ≤ cle 8057   # cap 8602  ℕcn 8984  ℤcz 9320  ℤ_≥cuz 9595  ...cfz 10077  seqcseq 10521  ♯chash 10849   ⇝ cli 11424  ∏cprod 11696

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 710  ax-5 1458  ax-7 1459  ax-gen 1460  ax-ie1 1504  ax-ie2 1505  ax-8 1515  ax-10 1516  ax-11 1517  ax-i12 1518  ax-bndl 1520  ax-4 1521  ax-17 1537  ax-i9 1541  ax-ial 1545  ax-i5r 1546  ax-13 2166  ax-14 2167  ax-ext 2175  ax-coll 4145  ax-sep 4148  ax-nul 4156  ax-pow 4204  ax-pr 4239  ax-un 4465  ax-setind 4570  ax-iinf 4621  ax-cnex 7965  ax-resscn 7966  ax-1cn 7967  ax-1re 7968  ax-icn 7969  ax-addcl 7970  ax-addrcl 7971  ax-mulcl 7972  ax-mulrcl 7973  ax-addcom 7974  ax-mulcom 7975  ax-addass 7976  ax-mulass 7977  ax-distr 7978  ax-i2m1 7979  ax-0lt1 7980  ax-1rid 7981  ax-0id 7982  ax-rnegex 7983  ax-precex 7984  ax-cnre 7985  ax-pre-ltirr 7986  ax-pre-ltwlin 7987  ax-pre-lttrn 7988  ax-pre-apti 7989  ax-pre-ltadd 7990  ax-pre-mulgt0 7991  ax-pre-mulext 7992  ax-arch 7993  ax-caucvg 7994

This theorem depends on definitions:  df-bi 117  df-dc 836  df-3or 981  df-3an 982  df-tru 1367  df-fal 1370  df-nf 1472  df-sb 1774  df-eu 2045  df-mo 2046  df-clab 2180  df-cleq 2186  df-clel 2189  df-nfc 2325  df-ne 2365  df-nel 2460  df-ral 2477  df-rex 2478  df-reu 2479  df-rmo 2480  df-rab 2481  df-v 2762  df-sbc 2987  df-csb 3082  df-dif 3156  df-un 3158  df-in 3160  df-ss 3167  df-nul 3448  df-if 3559  df-pw 3604  df-sn 3625  df-pr 3626  df-op 3628  df-uni 3837  df-int 3872  df-iun 3915  df-br 4031  df-opab 4092  df-mpt 4093  df-tr 4129  df-id 4325  df-po 4328  df-iso 4329  df-iord 4398  df-on 4400  df-ilim 4401  df-suc 4403  df-iom 4624  df-xp 4666  df-rel 4667  df-cnv 4668  df-co 4669  df-dm 4670  df-rn 4671  df-res 4672  df-ima 4673  df-iota 5216  df-fun 5257  df-fn 5258  df-f 5259  df-f1 5260  df-fo 5261  df-f1o 5262  df-fv 5263  df-isom 5264  df-riota 5874  df-ov 5922  df-oprab 5923  df-mpo 5924  df-1st 6195  df-2nd 6196  df-recs 6360  df-irdg 6425  df-frec 6446  df-1o 6471  df-oadd 6475  df-er 6589  df-en 6797  df-dom 6798  df-fin 6799  df-pnf 8058  df-mnf 8059  df-xr 8060  df-ltxr 8061  df-le 8062  df-sub 8194  df-neg 8195  df-reap 8596  df-ap 8603  df-div 8694  df-inn 8985  df-2 9043  df-3 9044  df-4 9045  df-n0 9244  df-z 9321  df-uz 9596  df-q 9688  df-rp 9723  df-fz 10078  df-fzo 10212  df-seqfrec 10522  df-exp 10613  df-ihash 10850  df-cj 10989  df-re 10990  df-im 10991  df-rsqrt 11145  df-abs 11146  df-clim 11425  df-proddc 11697

This theorem is referenced by: (None)