![]() |
Metamath Proof Explorer |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > nmrtri | Structured version Visualization version GIF version |
Description: Reverse triangle inequality for the norm of a subtraction. Problem 3 of [Kreyszig] p. 64. (Contributed by NM, 4-Dec-2006.) (Revised by Mario Carneiro, 4-Oct-2015.) |
Ref | Expression |
---|---|
nmf.x | ⊢ 𝑋 = (Base‘𝐺) |
nmf.n | ⊢ 𝑁 = (norm‘𝐺) |
nmmtri.m | ⊢ − = (-g‘𝐺) |
Ref | Expression |
---|---|
nmrtri | ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (abs‘((𝑁‘𝐴) − (𝑁‘𝐵))) ≤ (𝑁‘(𝐴 − 𝐵))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ngpms 22774 | . . . 4 ⊢ (𝐺 ∈ NrmGrp → 𝐺 ∈ MetSp) | |
2 | 1 | 3ad2ant1 1169 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐺 ∈ MetSp) |
3 | simp2 1173 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐴 ∈ 𝑋) | |
4 | simp3 1174 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐵 ∈ 𝑋) | |
5 | ngpgrp 22773 | . . . . 5 ⊢ (𝐺 ∈ NrmGrp → 𝐺 ∈ Grp) | |
6 | 5 | 3ad2ant1 1169 | . . . 4 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐺 ∈ Grp) |
7 | nmf.x | . . . . 5 ⊢ 𝑋 = (Base‘𝐺) | |
8 | eqid 2825 | . . . . 5 ⊢ (0g‘𝐺) = (0g‘𝐺) | |
9 | 7, 8 | grpidcl 17804 | . . . 4 ⊢ (𝐺 ∈ Grp → (0g‘𝐺) ∈ 𝑋) |
10 | 6, 9 | syl 17 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (0g‘𝐺) ∈ 𝑋) |
11 | eqid 2825 | . . . 4 ⊢ (dist‘𝐺) = (dist‘𝐺) | |
12 | 7, 11 | msrtri 22647 | . . 3 ⊢ ((𝐺 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ (0g‘𝐺) ∈ 𝑋)) → (abs‘((𝐴(dist‘𝐺)(0g‘𝐺)) − (𝐵(dist‘𝐺)(0g‘𝐺)))) ≤ (𝐴(dist‘𝐺)𝐵)) |
13 | 2, 3, 4, 10, 12 | syl13anc 1497 | . 2 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (abs‘((𝐴(dist‘𝐺)(0g‘𝐺)) − (𝐵(dist‘𝐺)(0g‘𝐺)))) ≤ (𝐴(dist‘𝐺)𝐵)) |
14 | nmf.n | . . . . . 6 ⊢ 𝑁 = (norm‘𝐺) | |
15 | 14, 7, 8, 11 | nmval 22764 | . . . . 5 ⊢ (𝐴 ∈ 𝑋 → (𝑁‘𝐴) = (𝐴(dist‘𝐺)(0g‘𝐺))) |
16 | 15 | 3ad2ant2 1170 | . . . 4 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝑁‘𝐴) = (𝐴(dist‘𝐺)(0g‘𝐺))) |
17 | 14, 7, 8, 11 | nmval 22764 | . . . . 5 ⊢ (𝐵 ∈ 𝑋 → (𝑁‘𝐵) = (𝐵(dist‘𝐺)(0g‘𝐺))) |
18 | 17 | 3ad2ant3 1171 | . . . 4 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝑁‘𝐵) = (𝐵(dist‘𝐺)(0g‘𝐺))) |
19 | 16, 18 | oveq12d 6923 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → ((𝑁‘𝐴) − (𝑁‘𝐵)) = ((𝐴(dist‘𝐺)(0g‘𝐺)) − (𝐵(dist‘𝐺)(0g‘𝐺)))) |
20 | 19 | fveq2d 6437 | . 2 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (abs‘((𝑁‘𝐴) − (𝑁‘𝐵))) = (abs‘((𝐴(dist‘𝐺)(0g‘𝐺)) − (𝐵(dist‘𝐺)(0g‘𝐺))))) |
21 | nmmtri.m | . . . 4 ⊢ − = (-g‘𝐺) | |
22 | 14, 7, 21, 11 | ngpds 22778 | . . 3 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐴(dist‘𝐺)𝐵) = (𝑁‘(𝐴 − 𝐵))) |
23 | 22 | eqcomd 2831 | . 2 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝑁‘(𝐴 − 𝐵)) = (𝐴(dist‘𝐺)𝐵)) |
24 | 13, 20, 23 | 3brtr4d 4905 | 1 ⊢ ((𝐺 ∈ NrmGrp ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (abs‘((𝑁‘𝐴) − (𝑁‘𝐵))) ≤ (𝑁‘(𝐴 − 𝐵))) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∧ w3a 1113 = wceq 1658 ∈ wcel 2166 class class class wbr 4873 ‘cfv 6123 (class class class)co 6905 ≤ cle 10392 − cmin 10585 abscabs 14351 Basecbs 16222 distcds 16314 0gc0g 16453 Grpcgrp 17776 -gcsg 17778 MetSpcms 22493 normcnm 22751 NrmGrpcngp 22752 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1896 ax-4 1910 ax-5 2011 ax-6 2077 ax-7 2114 ax-8 2168 ax-9 2175 ax-10 2194 ax-11 2209 ax-12 2222 ax-13 2391 ax-ext 2803 ax-rep 4994 ax-sep 5005 ax-nul 5013 ax-pow 5065 ax-pr 5127 ax-un 7209 ax-cnex 10308 ax-resscn 10309 ax-1cn 10310 ax-icn 10311 ax-addcl 10312 ax-addrcl 10313 ax-mulcl 10314 ax-mulrcl 10315 ax-mulcom 10316 ax-addass 10317 ax-mulass 10318 ax-distr 10319 ax-i2m1 10320 ax-1ne0 10321 ax-1rid 10322 ax-rnegex 10323 ax-rrecex 10324 ax-cnre 10325 ax-pre-lttri 10326 ax-pre-lttrn 10327 ax-pre-ltadd 10328 ax-pre-mulgt0 10329 ax-pre-sup 10330 |
This theorem depends on definitions: df-bi 199 df-an 387 df-or 881 df-3or 1114 df-3an 1115 df-tru 1662 df-ex 1881 df-nf 1885 df-sb 2070 df-mo 2605 df-eu 2640 df-clab 2812 df-cleq 2818 df-clel 2821 df-nfc 2958 df-ne 3000 df-nel 3103 df-ral 3122 df-rex 3123 df-reu 3124 df-rmo 3125 df-rab 3126 df-v 3416 df-sbc 3663 df-csb 3758 df-dif 3801 df-un 3803 df-in 3805 df-ss 3812 df-pss 3814 df-nul 4145 df-if 4307 df-pw 4380 df-sn 4398 df-pr 4400 df-tp 4402 df-op 4404 df-uni 4659 df-int 4698 df-iun 4742 df-br 4874 df-opab 4936 df-mpt 4953 df-tr 4976 df-id 5250 df-eprel 5255 df-po 5263 df-so 5264 df-fr 5301 df-we 5303 df-xp 5348 df-rel 5349 df-cnv 5350 df-co 5351 df-dm 5352 df-rn 5353 df-res 5354 df-ima 5355 df-pred 5920 df-ord 5966 df-on 5967 df-lim 5968 df-suc 5969 df-iota 6086 df-fun 6125 df-fn 6126 df-f 6127 df-f1 6128 df-fo 6129 df-f1o 6130 df-fv 6131 df-riota 6866 df-ov 6908 df-oprab 6909 df-mpt2 6910 df-om 7327 df-1st 7428 df-2nd 7429 df-wrecs 7672 df-recs 7734 df-rdg 7772 df-1o 7826 df-oadd 7830 df-er 8009 df-map 8124 df-en 8223 df-dom 8224 df-sdom 8225 df-fin 8226 df-sup 8617 df-inf 8618 df-pnf 10393 df-mnf 10394 df-xr 10395 df-ltxr 10396 df-le 10397 df-sub 10587 df-neg 10588 df-div 11010 df-nn 11351 df-2 11414 df-3 11415 df-4 11416 df-5 11417 df-6 11418 df-7 11419 df-8 11420 df-9 11421 df-n0 11619 df-z 11705 df-dec 11822 df-uz 11969 df-q 12072 df-rp 12113 df-xneg 12232 df-xadd 12233 df-xmul 12234 df-fz 12620 df-seq 13096 df-exp 13155 df-cj 14216 df-re 14217 df-im 14218 df-sqrt 14352 df-abs 14353 df-struct 16224 df-ndx 16225 df-slot 16226 df-base 16228 df-plusg 16318 df-mulr 16319 df-tset 16324 df-ple 16325 df-ds 16327 df-0g 16455 df-topgen 16457 df-xrs 16515 df-mgm 17595 df-sgrp 17637 df-mnd 17648 df-grp 17779 df-minusg 17780 df-sbg 17781 df-psmet 20098 df-xmet 20099 df-met 20100 df-bl 20101 df-mopn 20102 df-top 21069 df-topon 21086 df-topsp 21108 df-bases 21121 df-xms 22495 df-ms 22496 df-nm 22757 df-ngp 22758 |
This theorem is referenced by: nm2dif 22799 |
Copyright terms: Public domain | W3C validator |