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Theorem norm-ii-i 28597
Description: Triangle inequality for norms. Theorem 3.3(ii) of [Beran] p. 97. (Contributed by NM, 11-Aug-1999.) (New usage is discouraged.)
Hypotheses
Ref Expression
norm-ii.1 𝐴 ∈ ℋ
norm-ii.2 𝐵 ∈ ℋ
Assertion
Ref Expression
norm-ii-i (norm‘(𝐴 + 𝐵)) ≤ ((norm𝐴) + (norm𝐵))

Proof of Theorem norm-ii-i
StepHypRef Expression
1 1re 10490 . . . . . . . . . . 11 1 ∈ ℝ
2 ax-1cn 10444 . . . . . . . . . . . 12 1 ∈ ℂ
32cjrebi 14367 . . . . . . . . . . 11 (1 ∈ ℝ ↔ (∗‘1) = 1)
41, 3mpbi 231 . . . . . . . . . 10 (∗‘1) = 1
54oveq1i 7029 . . . . . . . . 9 ((∗‘1) · (𝐵 ·ih 𝐴)) = (1 · (𝐵 ·ih 𝐴))
6 norm-ii.2 . . . . . . . . . . 11 𝐵 ∈ ℋ
7 norm-ii.1 . . . . . . . . . . 11 𝐴 ∈ ℋ
86, 7hicli 28541 . . . . . . . . . 10 (𝐵 ·ih 𝐴) ∈ ℂ
98mulid2i 10495 . . . . . . . . 9 (1 · (𝐵 ·ih 𝐴)) = (𝐵 ·ih 𝐴)
105, 9eqtri 2818 . . . . . . . 8 ((∗‘1) · (𝐵 ·ih 𝐴)) = (𝐵 ·ih 𝐴)
117, 6hicli 28541 . . . . . . . . 9 (𝐴 ·ih 𝐵) ∈ ℂ
1211mulid2i 10495 . . . . . . . 8 (1 · (𝐴 ·ih 𝐵)) = (𝐴 ·ih 𝐵)
1310, 12oveq12i 7031 . . . . . . 7 (((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) = ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵))
14 abs1 14491 . . . . . . . 8 (abs‘1) = 1
152, 6, 7, 14normlem7 28576 . . . . . . 7 (((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ≤ (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))
1613, 15eqbrtrri 4987 . . . . . 6 ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵)) ≤ (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))
17 eqid 2794 . . . . . . . . . 10 -(((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) = -(((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵)))
182, 6, 7, 17normlem2 28571 . . . . . . . . 9 -(((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ∈ ℝ
192cjcli 14362 . . . . . . . . . . . 12 (∗‘1) ∈ ℂ
2019, 8mulcli 10497 . . . . . . . . . . 11 ((∗‘1) · (𝐵 ·ih 𝐴)) ∈ ℂ
212, 11mulcli 10497 . . . . . . . . . . 11 (1 · (𝐴 ·ih 𝐵)) ∈ ℂ
2220, 21addcli 10496 . . . . . . . . . 10 (((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ∈ ℂ
2322negrebi 10810 . . . . . . . . 9 (-(((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ∈ ℝ ↔ (((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ∈ ℝ)
2418, 23mpbi 231 . . . . . . . 8 (((∗‘1) · (𝐵 ·ih 𝐴)) + (1 · (𝐴 ·ih 𝐵))) ∈ ℝ
2513, 24eqeltrri 2879 . . . . . . 7 ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵)) ∈ ℝ
26 2re 11561 . . . . . . . 8 2 ∈ ℝ
27 hiidge0 28558 . . . . . . . . . . 11 (𝐴 ∈ ℋ → 0 ≤ (𝐴 ·ih 𝐴))
287, 27ax-mp 5 . . . . . . . . . 10 0 ≤ (𝐴 ·ih 𝐴)
29 hiidrcl 28555 . . . . . . . . . . . 12 (𝐴 ∈ ℋ → (𝐴 ·ih 𝐴) ∈ ℝ)
307, 29ax-mp 5 . . . . . . . . . . 11 (𝐴 ·ih 𝐴) ∈ ℝ
3130sqrtcli 14565 . . . . . . . . . 10 (0 ≤ (𝐴 ·ih 𝐴) → (√‘(𝐴 ·ih 𝐴)) ∈ ℝ)
3228, 31ax-mp 5 . . . . . . . . 9 (√‘(𝐴 ·ih 𝐴)) ∈ ℝ
33 hiidge0 28558 . . . . . . . . . . 11 (𝐵 ∈ ℋ → 0 ≤ (𝐵 ·ih 𝐵))
346, 33ax-mp 5 . . . . . . . . . 10 0 ≤ (𝐵 ·ih 𝐵)
35 hiidrcl 28555 . . . . . . . . . . . 12 (𝐵 ∈ ℋ → (𝐵 ·ih 𝐵) ∈ ℝ)
366, 35ax-mp 5 . . . . . . . . . . 11 (𝐵 ·ih 𝐵) ∈ ℝ
3736sqrtcli 14565 . . . . . . . . . 10 (0 ≤ (𝐵 ·ih 𝐵) → (√‘(𝐵 ·ih 𝐵)) ∈ ℝ)
3834, 37ax-mp 5 . . . . . . . . 9 (√‘(𝐵 ·ih 𝐵)) ∈ ℝ
3932, 38remulcli 10506 . . . . . . . 8 ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))) ∈ ℝ
4026, 39remulcli 10506 . . . . . . 7 (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))) ∈ ℝ
4130, 36readdcli 10505 . . . . . . 7 ((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) ∈ ℝ
4225, 40, 41leadd2i 11046 . . . . . 6 (((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵)) ≤ (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))) ↔ (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵))) ≤ (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))))
4316, 42mpbi 231 . . . . 5 (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵))) ≤ (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))))
447, 6, 7, 6normlem8 28577 . . . . . 6 ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) = (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐴 ·ih 𝐵) + (𝐵 ·ih 𝐴)))
4511, 8addcomi 10680 . . . . . . 7 ((𝐴 ·ih 𝐵) + (𝐵 ·ih 𝐴)) = ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵))
4645oveq2i 7030 . . . . . 6 (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐴 ·ih 𝐵) + (𝐵 ·ih 𝐴))) = (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵)))
4744, 46eqtri 2818 . . . . 5 ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) = (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + ((𝐵 ·ih 𝐴) + (𝐴 ·ih 𝐵)))
4832recni 10504 . . . . . . 7 (√‘(𝐴 ·ih 𝐴)) ∈ ℂ
4938recni 10504 . . . . . . 7 (√‘(𝐵 ·ih 𝐵)) ∈ ℂ
5048, 49binom2i 13424 . . . . . 6 (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2) = ((((√‘(𝐴 ·ih 𝐴))↑2) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))) + ((√‘(𝐵 ·ih 𝐵))↑2))
5148sqcli 13394 . . . . . . 7 ((√‘(𝐴 ·ih 𝐴))↑2) ∈ ℂ
52 2cn 11562 . . . . . . . 8 2 ∈ ℂ
5348, 49mulcli 10497 . . . . . . . 8 ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))) ∈ ℂ
5452, 53mulcli 10497 . . . . . . 7 (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))) ∈ ℂ
5549sqcli 13394 . . . . . . 7 ((√‘(𝐵 ·ih 𝐵))↑2) ∈ ℂ
5651, 54, 55add32i 10712 . . . . . 6 ((((√‘(𝐴 ·ih 𝐴))↑2) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))) + ((√‘(𝐵 ·ih 𝐵))↑2)) = ((((√‘(𝐴 ·ih 𝐴))↑2) + ((√‘(𝐵 ·ih 𝐵))↑2)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))))
5730sqsqrti 14569 . . . . . . . . 9 (0 ≤ (𝐴 ·ih 𝐴) → ((√‘(𝐴 ·ih 𝐴))↑2) = (𝐴 ·ih 𝐴))
5828, 57ax-mp 5 . . . . . . . 8 ((√‘(𝐴 ·ih 𝐴))↑2) = (𝐴 ·ih 𝐴)
5936sqsqrti 14569 . . . . . . . . 9 (0 ≤ (𝐵 ·ih 𝐵) → ((√‘(𝐵 ·ih 𝐵))↑2) = (𝐵 ·ih 𝐵))
6034, 59ax-mp 5 . . . . . . . 8 ((√‘(𝐵 ·ih 𝐵))↑2) = (𝐵 ·ih 𝐵)
6158, 60oveq12i 7031 . . . . . . 7 (((√‘(𝐴 ·ih 𝐴))↑2) + ((√‘(𝐵 ·ih 𝐵))↑2)) = ((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵))
6261oveq1i 7029 . . . . . 6 ((((√‘(𝐴 ·ih 𝐴))↑2) + ((√‘(𝐵 ·ih 𝐵))↑2)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵))))) = (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))))
6350, 56, 623eqtri 2822 . . . . 5 (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2) = (((𝐴 ·ih 𝐴) + (𝐵 ·ih 𝐵)) + (2 · ((√‘(𝐴 ·ih 𝐴)) · (√‘(𝐵 ·ih 𝐵)))))
6443, 47, 633brtr4i 4994 . . . 4 ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ≤ (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)
657, 6hvaddcli 28478 . . . . . 6 (𝐴 + 𝐵) ∈ ℋ
66 hiidge0 28558 . . . . . 6 ((𝐴 + 𝐵) ∈ ℋ → 0 ≤ ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)))
6765, 66ax-mp 5 . . . . 5 0 ≤ ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))
6832, 38readdcli 10505 . . . . . 6 ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵))) ∈ ℝ
6968sqge0i 13401 . . . . 5 0 ≤ (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)
70 hiidrcl 28555 . . . . . . 7 ((𝐴 + 𝐵) ∈ ℋ → ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ∈ ℝ)
7165, 70ax-mp 5 . . . . . 6 ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ∈ ℝ
7268resqcli 13399 . . . . . 6 (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2) ∈ ℝ
7371, 72sqrtlei 14582 . . . . 5 ((0 ≤ ((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ∧ 0 ≤ (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)) → (((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ≤ (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2) ↔ (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))) ≤ (√‘(((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2))))
7467, 69, 73mp2an 688 . . . 4 (((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)) ≤ (((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2) ↔ (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))) ≤ (√‘(((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)))
7564, 74mpbi 231 . . 3 (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))) ≤ (√‘(((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2))
7630sqrtge0i 14570 . . . . . 6 (0 ≤ (𝐴 ·ih 𝐴) → 0 ≤ (√‘(𝐴 ·ih 𝐴)))
7728, 76ax-mp 5 . . . . 5 0 ≤ (√‘(𝐴 ·ih 𝐴))
7836sqrtge0i 14570 . . . . . 6 (0 ≤ (𝐵 ·ih 𝐵) → 0 ≤ (√‘(𝐵 ·ih 𝐵)))
7934, 78ax-mp 5 . . . . 5 0 ≤ (√‘(𝐵 ·ih 𝐵))
8032, 38addge0i 11030 . . . . 5 ((0 ≤ (√‘(𝐴 ·ih 𝐴)) ∧ 0 ≤ (√‘(𝐵 ·ih 𝐵))) → 0 ≤ ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵))))
8177, 79, 80mp2an 688 . . . 4 0 ≤ ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))
8268sqrtsqi 14568 . . . 4 (0 ≤ ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵))) → (√‘(((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)) = ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵))))
8381, 82ax-mp 5 . . 3 (√‘(((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))↑2)) = ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))
8475, 83breqtri 4989 . 2 (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))) ≤ ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))
85 normval 28584 . . 3 ((𝐴 + 𝐵) ∈ ℋ → (norm‘(𝐴 + 𝐵)) = (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵))))
8665, 85ax-mp 5 . 2 (norm‘(𝐴 + 𝐵)) = (√‘((𝐴 + 𝐵) ·ih (𝐴 + 𝐵)))
87 normval 28584 . . . 4 (𝐴 ∈ ℋ → (norm𝐴) = (√‘(𝐴 ·ih 𝐴)))
887, 87ax-mp 5 . . 3 (norm𝐴) = (√‘(𝐴 ·ih 𝐴))
89 normval 28584 . . . 4 (𝐵 ∈ ℋ → (norm𝐵) = (√‘(𝐵 ·ih 𝐵)))
906, 89ax-mp 5 . . 3 (norm𝐵) = (√‘(𝐵 ·ih 𝐵))
9188, 90oveq12i 7031 . 2 ((norm𝐴) + (norm𝐵)) = ((√‘(𝐴 ·ih 𝐴)) + (√‘(𝐵 ·ih 𝐵)))
9284, 86, 913brtr4i 4994 1 (norm‘(𝐴 + 𝐵)) ≤ ((norm𝐴) + (norm𝐵))
Colors of variables: wff setvar class
Syntax hints:  wb 207   = wceq 1522  wcel 2080   class class class wbr 4964  cfv 6228  (class class class)co 7019  cr 10385  0cc0 10386  1c1 10387   + caddc 10389   · cmul 10391  cle 10525  -cneg 10720  2c2 11542  cexp 13279  ccj 14289  csqrt 14426  chba 28379   + cva 28380   ·ih csp 28382  normcno 28383
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1778  ax-4 1792  ax-5 1889  ax-6 1948  ax-7 1993  ax-8 2082  ax-9 2090  ax-10 2111  ax-11 2125  ax-12 2140  ax-13 2343  ax-ext 2768  ax-sep 5097  ax-nul 5104  ax-pow 5160  ax-pr 5224  ax-un 7322  ax-cnex 10442  ax-resscn 10443  ax-1cn 10444  ax-icn 10445  ax-addcl 10446  ax-addrcl 10447  ax-mulcl 10448  ax-mulrcl 10449  ax-mulcom 10450  ax-addass 10451  ax-mulass 10452  ax-distr 10453  ax-i2m1 10454  ax-1ne0 10455  ax-1rid 10456  ax-rnegex 10457  ax-rrecex 10458  ax-cnre 10459  ax-pre-lttri 10460  ax-pre-lttrn 10461  ax-pre-ltadd 10462  ax-pre-mulgt0 10463  ax-pre-sup 10464  ax-hfvadd 28460  ax-hv0cl 28463  ax-hfvmul 28465  ax-hvmulass 28467  ax-hvmul0 28470  ax-hfi 28539  ax-his1 28542  ax-his2 28543  ax-his3 28544  ax-his4 28545
This theorem depends on definitions:  df-bi 208  df-an 397  df-or 843  df-3or 1081  df-3an 1082  df-tru 1525  df-ex 1763  df-nf 1767  df-sb 2042  df-mo 2575  df-eu 2611  df-clab 2775  df-cleq 2787  df-clel 2862  df-nfc 2934  df-ne 2984  df-nel 3090  df-ral 3109  df-rex 3110  df-reu 3111  df-rmo 3112  df-rab 3113  df-v 3438  df-sbc 3708  df-csb 3814  df-dif 3864  df-un 3866  df-in 3868  df-ss 3876  df-pss 3878  df-nul 4214  df-if 4384  df-pw 4457  df-sn 4475  df-pr 4477  df-tp 4479  df-op 4481  df-uni 4748  df-iun 4829  df-br 4965  df-opab 5027  df-mpt 5044  df-tr 5067  df-id 5351  df-eprel 5356  df-po 5365  df-so 5366  df-fr 5405  df-we 5407  df-xp 5452  df-rel 5453  df-cnv 5454  df-co 5455  df-dm 5456  df-rn 5457  df-res 5458  df-ima 5459  df-pred 6026  df-ord 6072  df-on 6073  df-lim 6074  df-suc 6075  df-iota 6192  df-fun 6230  df-fn 6231  df-f 6232  df-f1 6233  df-fo 6234  df-f1o 6235  df-fv 6236  df-riota 6980  df-ov 7022  df-oprab 7023  df-mpo 7024  df-om 7440  df-2nd 7549  df-wrecs 7801  df-recs 7863  df-rdg 7901  df-er 8142  df-en 8361  df-dom 8362  df-sdom 8363  df-sup 8755  df-pnf 10526  df-mnf 10527  df-xr 10528  df-ltxr 10529  df-le 10530  df-sub 10721  df-neg 10722  df-div 11148  df-nn 11489  df-2 11550  df-3 11551  df-4 11552  df-n0 11748  df-z 11832  df-uz 12094  df-rp 12240  df-seq 13220  df-exp 13280  df-cj 14292  df-re 14293  df-im 14294  df-sqrt 14428  df-abs 14429  df-hnorm 28428  df-hvsub 28431
This theorem is referenced by:  norm-ii  28598  norm3difi  28607
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