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Mirrors > Home > ILE Home > Th. List > mstri | GIF version |
Description: Triangle inequality for the distance function of a metric space. Definition 14-1.1(d) of [Gleason] p. 223. (Contributed by Mario Carneiro, 2-Oct-2015.) |
Ref | Expression |
---|---|
mscl.x | ⊢ 𝑋 = (Base‘𝑀) |
mscl.d | ⊢ 𝐷 = (dist‘𝑀) |
Ref | Expression |
---|---|
mstri | ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴𝐷𝐵) ≤ ((𝐴𝐷𝐶) + (𝐶𝐷𝐵))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | mscl.x | . . . 4 ⊢ 𝑋 = (Base‘𝑀) | |
2 | mscl.d | . . . 4 ⊢ 𝐷 = (dist‘𝑀) | |
3 | 1, 2 | msmet2 14260 | . . 3 ⊢ (𝑀 ∈ MetSp → (𝐷 ↾ (𝑋 × 𝑋)) ∈ (Met‘𝑋)) |
4 | mettri 14169 | . . 3 ⊢ (((𝐷 ↾ (𝑋 × 𝑋)) ∈ (Met‘𝑋) ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐵) ≤ ((𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐶) + (𝐶(𝐷 ↾ (𝑋 × 𝑋))𝐵))) | |
5 | 3, 4 | sylan 283 | . 2 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐵) ≤ ((𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐶) + (𝐶(𝐷 ↾ (𝑋 × 𝑋))𝐵))) |
6 | simpr1 1004 | . . 3 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → 𝐴 ∈ 𝑋) | |
7 | simpr2 1005 | . . 3 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → 𝐵 ∈ 𝑋) | |
8 | 6, 7 | ovresd 6029 | . 2 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐵) = (𝐴𝐷𝐵)) |
9 | simpr3 1006 | . . . 4 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → 𝐶 ∈ 𝑋) | |
10 | 6, 9 | ovresd 6029 | . . 3 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐶) = (𝐴𝐷𝐶)) |
11 | 9, 7 | ovresd 6029 | . . 3 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐶(𝐷 ↾ (𝑋 × 𝑋))𝐵) = (𝐶𝐷𝐵)) |
12 | 10, 11 | oveq12d 5906 | . 2 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → ((𝐴(𝐷 ↾ (𝑋 × 𝑋))𝐶) + (𝐶(𝐷 ↾ (𝑋 × 𝑋))𝐵)) = ((𝐴𝐷𝐶) + (𝐶𝐷𝐵))) |
13 | 5, 8, 12 | 3brtr3d 4046 | 1 ⊢ ((𝑀 ∈ MetSp ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐶 ∈ 𝑋)) → (𝐴𝐷𝐵) ≤ ((𝐴𝐷𝐶) + (𝐶𝐷𝐵))) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 104 ∧ w3a 979 = wceq 1363 ∈ wcel 2158 class class class wbr 4015 × cxp 4636 ↾ cres 4640 ‘cfv 5228 (class class class)co 5888 + caddc 7828 ≤ cle 8007 Basecbs 12476 distcds 12560 Metcmet 13723 MetSpcms 14133 |
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 1457 ax-7 1458 ax-gen 1459 ax-ie1 1503 ax-ie2 1504 ax-8 1514 ax-10 1515 ax-11 1516 ax-i12 1517 ax-bndl 1519 ax-4 1520 ax-17 1536 ax-i9 1540 ax-ial 1544 ax-i5r 1545 ax-13 2160 ax-14 2161 ax-ext 2169 ax-coll 4130 ax-sep 4133 ax-nul 4141 ax-pow 4186 ax-pr 4221 ax-un 4445 ax-setind 4548 ax-iinf 4599 ax-cnex 7916 ax-resscn 7917 ax-1cn 7918 ax-1re 7919 ax-icn 7920 ax-addcl 7921 ax-addrcl 7922 ax-mulcl 7923 ax-mulrcl 7924 ax-addcom 7925 ax-mulcom 7926 ax-addass 7927 ax-mulass 7928 ax-distr 7929 ax-i2m1 7930 ax-0lt1 7931 ax-1rid 7932 ax-0id 7933 ax-rnegex 7934 ax-precex 7935 ax-cnre 7936 ax-pre-ltirr 7937 ax-pre-ltwlin 7938 ax-pre-lttrn 7939 ax-pre-apti 7940 ax-pre-ltadd 7941 ax-pre-mulgt0 7942 ax-pre-mulext 7943 ax-arch 7944 ax-caucvg 7945 |
This theorem depends on definitions: df-bi 117 df-stab 832 df-dc 836 df-3or 980 df-3an 981 df-tru 1366 df-fal 1369 df-nf 1471 df-sb 1773 df-eu 2039 df-mo 2040 df-clab 2174 df-cleq 2180 df-clel 2183 df-nfc 2318 df-ne 2358 df-nel 2453 df-ral 2470 df-rex 2471 df-reu 2472 df-rmo 2473 df-rab 2474 df-v 2751 df-sbc 2975 df-csb 3070 df-dif 3143 df-un 3145 df-in 3147 df-ss 3154 df-nul 3435 df-if 3547 df-pw 3589 df-sn 3610 df-pr 3611 df-op 3613 df-uni 3822 df-int 3857 df-iun 3900 df-br 4016 df-opab 4077 df-mpt 4078 df-tr 4114 df-id 4305 df-po 4308 df-iso 4309 df-iord 4378 df-on 4380 df-ilim 4381 df-suc 4383 df-iom 4602 df-xp 4644 df-rel 4645 df-cnv 4646 df-co 4647 df-dm 4648 df-rn 4649 df-res 4650 df-ima 4651 df-iota 5190 df-fun 5230 df-fn 5231 df-f 5232 df-f1 5233 df-fo 5234 df-f1o 5235 df-fv 5236 df-isom 5237 df-riota 5844 df-ov 5891 df-oprab 5892 df-mpo 5893 df-1st 6155 df-2nd 6156 df-recs 6320 df-frec 6406 df-map 6664 df-sup 6997 df-inf 6998 df-pnf 8008 df-mnf 8009 df-xr 8010 df-ltxr 8011 df-le 8012 df-sub 8144 df-neg 8145 df-reap 8546 df-ap 8553 df-div 8644 df-inn 8934 df-2 8992 df-3 8993 df-4 8994 df-5 8995 df-6 8996 df-7 8997 df-8 8998 df-9 8999 df-n0 9191 df-z 9268 df-uz 9543 df-q 9634 df-rp 9668 df-xneg 9786 df-xadd 9787 df-seqfrec 10460 df-exp 10534 df-cj 10865 df-re 10866 df-im 10867 df-rsqrt 11021 df-abs 11022 df-ndx 12479 df-slot 12480 df-base 12482 df-tset 12570 df-rest 12708 df-topn 12709 df-topgen 12727 df-psmet 13729 df-xmet 13730 df-met 13731 df-bl 13732 df-mopn 13733 df-top 13794 df-topon 13807 df-topsp 13827 df-bases 13839 df-xms 14135 df-ms 14136 |
This theorem is referenced by: (None) |
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