Theorem mulcnsr 9957

Description: Multiplication of complex numbers in terms of signed reals. (Contributed by NM, 9-Aug-1995.) (New usage is discouraged.)

Assertion

Ref	Expression
mulcnsr	⊢ (((𝐴 ∈ R ∧ 𝐵 ∈ R) ∧ (𝐶 ∈ R ∧ 𝐷 ∈ R)) → (⟨𝐴, 𝐵⟩ · ⟨𝐶, 𝐷⟩) = ⟨((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))), ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷))⟩)

Proof of Theorem mulcnsr

Dummy variables 𝑥 𝑦 𝑧 𝑤 𝑣 𝑢 𝑓 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		opex 4932	. 2 ⊢ ⟨((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))), ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷))⟩ ∈ V
2		oveq1 6657	. . . . 5 ⊢ (𝑤 = 𝐴 → (𝑤 ·R 𝑢) = (𝐴 ·R 𝑢))
3		oveq1 6657	. . . . . 6 ⊢ (𝑣 = 𝐵 → (𝑣 ·R 𝑓) = (𝐵 ·R 𝑓))
4	3	oveq2d 6666	. . . . 5 ⊢ (𝑣 = 𝐵 → (-1R ·R (𝑣 ·R 𝑓)) = (-1R ·R (𝐵 ·R 𝑓)))
5	2, 4	oveqan12d 6669	. . . 4 ⊢ ((𝑤 = 𝐴 ∧ 𝑣 = 𝐵) → ((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))) = ((𝐴 ·R 𝑢) +R (-1R ·R (𝐵 ·R 𝑓))))
6		oveq1 6657	. . . . 5 ⊢ (𝑣 = 𝐵 → (𝑣 ·R 𝑢) = (𝐵 ·R 𝑢))
7		oveq1 6657	. . . . 5 ⊢ (𝑤 = 𝐴 → (𝑤 ·R 𝑓) = (𝐴 ·R 𝑓))
8	6, 7	oveqan12rd 6670	. . . 4 ⊢ ((𝑤 = 𝐴 ∧ 𝑣 = 𝐵) → ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓)) = ((𝐵 ·R 𝑢) +R (𝐴 ·R 𝑓)))
9	5, 8	opeq12d 4410	. . 3 ⊢ ((𝑤 = 𝐴 ∧ 𝑣 = 𝐵) → ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩ = ⟨((𝐴 ·R 𝑢) +R (-1R ·R (𝐵 ·R 𝑓))), ((𝐵 ·R 𝑢) +R (𝐴 ·R 𝑓))⟩)
10		oveq2 6658	. . . . 5 ⊢ (𝑢 = 𝐶 → (𝐴 ·R 𝑢) = (𝐴 ·R 𝐶))
11		oveq2 6658	. . . . . 6 ⊢ (𝑓 = 𝐷 → (𝐵 ·R 𝑓) = (𝐵 ·R 𝐷))
12	11	oveq2d 6666	. . . . 5 ⊢ (𝑓 = 𝐷 → (-1R ·R (𝐵 ·R 𝑓)) = (-1R ·R (𝐵 ·R 𝐷)))
13	10, 12	oveqan12d 6669	. . . 4 ⊢ ((𝑢 = 𝐶 ∧ 𝑓 = 𝐷) → ((𝐴 ·R 𝑢) +R (-1R ·R (𝐵 ·R 𝑓))) = ((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))))
14		oveq2 6658	. . . . 5 ⊢ (𝑢 = 𝐶 → (𝐵 ·R 𝑢) = (𝐵 ·R 𝐶))
15		oveq2 6658	. . . . 5 ⊢ (𝑓 = 𝐷 → (𝐴 ·R 𝑓) = (𝐴 ·R 𝐷))
16	14, 15	oveqan12d 6669	. . . 4 ⊢ ((𝑢 = 𝐶 ∧ 𝑓 = 𝐷) → ((𝐵 ·R 𝑢) +R (𝐴 ·R 𝑓)) = ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷)))
17	13, 16	opeq12d 4410	. . 3 ⊢ ((𝑢 = 𝐶 ∧ 𝑓 = 𝐷) → ⟨((𝐴 ·R 𝑢) +R (-1R ·R (𝐵 ·R 𝑓))), ((𝐵 ·R 𝑢) +R (𝐴 ·R 𝑓))⟩ = ⟨((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))), ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷))⟩)
18	9, 17	sylan9eq 2676	. 2 ⊢ (((𝑤 = 𝐴 ∧ 𝑣 = 𝐵) ∧ (𝑢 = 𝐶 ∧ 𝑓 = 𝐷)) → ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩ = ⟨((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))), ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷))⟩)
19		df-mul 9948	. . 3 ⊢ · = {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ ((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩))}
20		df-c 9942	. . . . . . 7 ⊢ ℂ = (R × R)
21	20	eleq2i 2693	. . . . . 6 ⊢ (𝑥 ∈ ℂ ↔ 𝑥 ∈ (R × R))
22	20	eleq2i 2693	. . . . . 6 ⊢ (𝑦 ∈ ℂ ↔ 𝑦 ∈ (R × R))
23	21, 22	anbi12i 733	. . . . 5 ⊢ ((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ↔ (𝑥 ∈ (R × R) ∧ 𝑦 ∈ (R × R)))
24	23	anbi1i 731	. . . 4 ⊢ (((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩)) ↔ ((𝑥 ∈ (R × R) ∧ 𝑦 ∈ (R × R)) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩)))
25	24	oprabbii 6710	. . 3 ⊢ {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ ((𝑥 ∈ ℂ ∧ 𝑦 ∈ ℂ) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩))} = {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ ((𝑥 ∈ (R × R) ∧ 𝑦 ∈ (R × R)) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩))}
26	19, 25	eqtri 2644	. 2 ⊢ · = {⟨⟨𝑥, 𝑦⟩, 𝑧⟩ ∣ ((𝑥 ∈ (R × R) ∧ 𝑦 ∈ (R × R)) ∧ ∃𝑤∃𝑣∃𝑢∃𝑓((𝑥 = ⟨𝑤, 𝑣⟩ ∧ 𝑦 = ⟨𝑢, 𝑓⟩) ∧ 𝑧 = ⟨((𝑤 ·R 𝑢) +R (-1R ·R (𝑣 ·R 𝑓))), ((𝑣 ·R 𝑢) +R (𝑤 ·R 𝑓))⟩))}
27	1, 18, 26	ov3 6797	1 ⊢ (((𝐴 ∈ R ∧ 𝐵 ∈ R) ∧ (𝐶 ∈ R ∧ 𝐷 ∈ R)) → (⟨𝐴, 𝐵⟩ · ⟨𝐶, 𝐷⟩) = ⟨((𝐴 ·R 𝐶) +R (-1R ·R (𝐵 ·R 𝐷))), ((𝐵 ·R 𝐶) +R (𝐴 ·R 𝐷))⟩)

Syntax hints:   → wi 4   ∧ wa 384   = wceq 1483  ∃wex 1704   ∈ wcel 1990  ⟨cop 4183   × cxp 5112  (class class class)co 6650  {coprab 6651  Rcnr 9687  -1_Rcm1r 9690   +_R cplr 9691   ·_R cmr 9692  ℂcc 9934   · cmul 9941

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1722  ax-4 1737  ax-5 1839  ax-6 1888  ax-7 1935  ax-9 1999  ax-10 2019  ax-11 2034  ax-12 2047  ax-13 2246  ax-ext 2602  ax-sep 4781  ax-nul 4789  ax-pr 4906

This theorem depends on definitions:  df-bi 197  df-or 385  df-an 386  df-3an 1039  df-tru 1486  df-ex 1705  df-nf 1710  df-sb 1881  df-eu 2474  df-mo 2475  df-clab 2609  df-cleq 2615  df-clel 2618  df-nfc 2753  df-ral 2917  df-rex 2918  df-rab 2921  df-v 3202  df-sbc 3436  df-dif 3577  df-un 3579  df-in 3581  df-ss 3588  df-nul 3916  df-if 4087  df-sn 4178  df-pr 4180  df-op 4184  df-uni 4437  df-br 4654  df-opab 4713  df-id 5024  df-xp 5120  df-rel 5121  df-cnv 5122  df-co 5123  df-dm 5124  df-iota 5851  df-fun 5890  df-fv 5896  df-ov 6653  df-oprab 6654  df-c 9942  df-mul 9948

This theorem is referenced by:  mulresr  9960  mulcnsrec  9965  axmulf  9967  axi2m1  9980  axcnre  9985