Theorem mulasspi 9679

Description: Multiplication of positive integers is associative. (Contributed by NM, 21-Sep-1995.) (New usage is discouraged.)

Assertion

Ref	Expression
mulasspi	⊢ ((𝐴 ·N 𝐵) ·N 𝐶) = (𝐴 ·N (𝐵 ·N 𝐶))

Proof of Theorem mulasspi

Step	Hyp	Ref	Expression
1		pinn 9660	. . . 4 ⊢ (𝐴 ∈ N → 𝐴 ∈ ω)
2		pinn 9660	. . . 4 ⊢ (𝐵 ∈ N → 𝐵 ∈ ω)
3		pinn 9660	. . . 4 ⊢ (𝐶 ∈ N → 𝐶 ∈ ω)
4		nnmass 7664	. . . 4 ⊢ ((𝐴 ∈ ω ∧ 𝐵 ∈ ω ∧ 𝐶 ∈ ω) → ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
5	1, 2, 3, 4	syl3an 1365	. . 3 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N ∧ 𝐶 ∈ N) → ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
6		mulclpi 9675	. . . . . 6 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N) → (𝐴 ·N 𝐵) ∈ N)
7		mulpiord 9667	. . . . . 6 ⊢ (((𝐴 ·N 𝐵) ∈ N ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = ((𝐴 ·N 𝐵) ·𝑜 𝐶))
8	6, 7	sylan 488	. . . . 5 ⊢ (((𝐴 ∈ N ∧ 𝐵 ∈ N) ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = ((𝐴 ·N 𝐵) ·𝑜 𝐶))
9		mulpiord 9667	. . . . . . 7 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N) → (𝐴 ·N 𝐵) = (𝐴 ·𝑜 𝐵))
10	9	oveq1d 6630	. . . . . 6 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N) → ((𝐴 ·N 𝐵) ·𝑜 𝐶) = ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶))
11	10	adantr 481	. . . . 5 ⊢ (((𝐴 ∈ N ∧ 𝐵 ∈ N) ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·𝑜 𝐶) = ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶))
12	8, 11	eqtrd 2655	. . . 4 ⊢ (((𝐴 ∈ N ∧ 𝐵 ∈ N) ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶))
13	12	3impa 1256	. . 3 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = ((𝐴 ·𝑜 𝐵) ·𝑜 𝐶))
14		mulclpi 9675	. . . . . 6 ⊢ ((𝐵 ∈ N ∧ 𝐶 ∈ N) → (𝐵 ·N 𝐶) ∈ N)
15		mulpiord 9667	. . . . . 6 ⊢ ((𝐴 ∈ N ∧ (𝐵 ·N 𝐶) ∈ N) → (𝐴 ·N (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·N 𝐶)))
16	14, 15	sylan2 491	. . . . 5 ⊢ ((𝐴 ∈ N ∧ (𝐵 ∈ N ∧ 𝐶 ∈ N)) → (𝐴 ·N (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·N 𝐶)))
17		mulpiord 9667	. . . . . . 7 ⊢ ((𝐵 ∈ N ∧ 𝐶 ∈ N) → (𝐵 ·N 𝐶) = (𝐵 ·𝑜 𝐶))
18	17	oveq2d 6631	. . . . . 6 ⊢ ((𝐵 ∈ N ∧ 𝐶 ∈ N) → (𝐴 ·𝑜 (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
19	18	adantl 482	. . . . 5 ⊢ ((𝐴 ∈ N ∧ (𝐵 ∈ N ∧ 𝐶 ∈ N)) → (𝐴 ·𝑜 (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
20	16, 19	eqtrd 2655	. . . 4 ⊢ ((𝐴 ∈ N ∧ (𝐵 ∈ N ∧ 𝐶 ∈ N)) → (𝐴 ·N (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
21	20	3impb 1257	. . 3 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N ∧ 𝐶 ∈ N) → (𝐴 ·N (𝐵 ·N 𝐶)) = (𝐴 ·𝑜 (𝐵 ·𝑜 𝐶)))
22	5, 13, 21	3eqtr4d 2665	. 2 ⊢ ((𝐴 ∈ N ∧ 𝐵 ∈ N ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = (𝐴 ·N (𝐵 ·N 𝐶)))
23		dmmulpi 9673	. . 3 ⊢ dom ·N = (N × N)
24		0npi 9664	. . 3 ⊢ ¬ ∅ ∈ N
25	23, 24	ndmovass 6787	. 2 ⊢ (¬ (𝐴 ∈ N ∧ 𝐵 ∈ N ∧ 𝐶 ∈ N) → ((𝐴 ·N 𝐵) ·N 𝐶) = (𝐴 ·N (𝐵 ·N 𝐶)))
26	22, 25	pm2.61i 176	1 ⊢ ((𝐴 ·N 𝐵) ·N 𝐶) = (𝐴 ·N (𝐵 ·N 𝐶))

Syntax hints:   ∧ wa 384   ∧ w3a 1036   = wceq 1480   ∈ wcel 1987  (class class class)co 6615  ωcom 7027   ·_𝑜 comu 7518  Ncnpi 9626   ·_N cmi 9628

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1719  ax-4 1734  ax-5 1836  ax-6 1885  ax-7 1932  ax-8 1989  ax-9 1996  ax-10 2016  ax-11 2031  ax-12 2044  ax-13 2245  ax-ext 2601  ax-sep 4751  ax-nul 4759  ax-pow 4813  ax-pr 4877  ax-un 6914

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3or 1037  df-3an 1038  df-tru 1483  df-ex 1702  df-nf 1707  df-sb 1878  df-eu 2473  df-mo 2474  df-clab 2608  df-cleq 2614  df-clel 2617  df-nfc 2750  df-ne 2791  df-ral 2913  df-rex 2914  df-reu 2915  df-rab 2917  df-v 3192  df-sbc 3423  df-csb 3520  df-dif 3563  df-un 3565  df-in 3567  df-ss 3574  df-pss 3576  df-nul 3898  df-if 4065  df-pw 4138  df-sn 4156  df-pr 4158  df-tp 4160  df-op 4162  df-uni 4410  df-iun 4494  df-br 4624  df-opab 4684  df-mpt 4685  df-tr 4723  df-eprel 4995  df-id 4999  df-po 5005  df-so 5006  df-fr 5043  df-we 5045  df-xp 5090  df-rel 5091  df-cnv 5092  df-co 5093  df-dm 5094  df-rn 5095  df-res 5096  df-ima 5097  df-pred 5649  df-ord 5695  df-on 5696  df-lim 5697  df-suc 5698  df-iota 5820  df-fun 5859  df-fn 5860  df-f 5861  df-f1 5862  df-fo 5863  df-f1o 5864  df-fv 5865  df-ov 6618  df-oprab 6619  df-mpt2 6620  df-om 7028  df-1st 7128  df-2nd 7129  df-wrecs 7367  df-recs 7428  df-rdg 7466  df-oadd 7524  df-omul 7525  df-ni 9654  df-mi 9656

This theorem is referenced by:  enqer  9703  adderpqlem  9736  mulerpqlem  9737  addassnq  9740  mulassnq  9741  mulcanenq  9742  distrnq  9743  ltsonq  9751  lterpq  9752  ltanq  9753  ltmnq  9754  ltexnq  9757