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Mirrors > Home > MPE Home > Th. List > metss2 | Structured version Visualization version GIF version |
Description: If the metric 𝐷 is "strongly finer" than 𝐶 (meaning that there is a positive real constant 𝑅 such that 𝐶(𝑥, 𝑦) ≤ 𝑅 · 𝐷(𝑥, 𝑦)), then 𝐷 generates a finer topology. (Using this theorem twice in each direction states that if two metrics are strongly equivalent, then they generate the same topology.) (Contributed by Mario Carneiro, 14-Sep-2015.) |
Ref | Expression |
---|---|
metequiv.3 | ⊢ 𝐽 = (MetOpen‘𝐶) |
metequiv.4 | ⊢ 𝐾 = (MetOpen‘𝐷) |
metss2.1 | ⊢ (𝜑 → 𝐶 ∈ (Met‘𝑋)) |
metss2.2 | ⊢ (𝜑 → 𝐷 ∈ (Met‘𝑋)) |
metss2.3 | ⊢ (𝜑 → 𝑅 ∈ ℝ+) |
metss2.4 | ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥𝐶𝑦) ≤ (𝑅 · (𝑥𝐷𝑦))) |
Ref | Expression |
---|---|
metss2 | ⊢ (𝜑 → 𝐽 ⊆ 𝐾) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpr 477 | . . . . 5 ⊢ ((𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+) → 𝑟 ∈ ℝ+) | |
2 | metss2.3 | . . . . 5 ⊢ (𝜑 → 𝑅 ∈ ℝ+) | |
3 | rpdivcl 11856 | . . . . 5 ⊢ ((𝑟 ∈ ℝ+ ∧ 𝑅 ∈ ℝ+) → (𝑟 / 𝑅) ∈ ℝ+) | |
4 | 1, 2, 3 | syl2anr 495 | . . . 4 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → (𝑟 / 𝑅) ∈ ℝ+) |
5 | metequiv.3 | . . . . 5 ⊢ 𝐽 = (MetOpen‘𝐶) | |
6 | metequiv.4 | . . . . 5 ⊢ 𝐾 = (MetOpen‘𝐷) | |
7 | metss2.1 | . . . . 5 ⊢ (𝜑 → 𝐶 ∈ (Met‘𝑋)) | |
8 | metss2.2 | . . . . 5 ⊢ (𝜑 → 𝐷 ∈ (Met‘𝑋)) | |
9 | metss2.4 | . . . . 5 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑦 ∈ 𝑋)) → (𝑥𝐶𝑦) ≤ (𝑅 · (𝑥𝐷𝑦))) | |
10 | 5, 6, 7, 8, 2, 9 | metss2lem 22316 | . . . 4 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟)) |
11 | oveq2 6658 | . . . . . 6 ⊢ (𝑠 = (𝑟 / 𝑅) → (𝑥(ball‘𝐷)𝑠) = (𝑥(ball‘𝐷)(𝑟 / 𝑅))) | |
12 | 11 | sseq1d 3632 | . . . . 5 ⊢ (𝑠 = (𝑟 / 𝑅) → ((𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟) ↔ (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟))) |
13 | 12 | rspcev 3309 | . . . 4 ⊢ (((𝑟 / 𝑅) ∈ ℝ+ ∧ (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟)) → ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
14 | 4, 10, 13 | syl2anc 693 | . . 3 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
15 | 14 | ralrimivva 2971 | . 2 ⊢ (𝜑 → ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
16 | metxmet 22139 | . . . 4 ⊢ (𝐶 ∈ (Met‘𝑋) → 𝐶 ∈ (∞Met‘𝑋)) | |
17 | 7, 16 | syl 17 | . . 3 ⊢ (𝜑 → 𝐶 ∈ (∞Met‘𝑋)) |
18 | metxmet 22139 | . . . 4 ⊢ (𝐷 ∈ (Met‘𝑋) → 𝐷 ∈ (∞Met‘𝑋)) | |
19 | 8, 18 | syl 17 | . . 3 ⊢ (𝜑 → 𝐷 ∈ (∞Met‘𝑋)) |
20 | 5, 6 | metss 22313 | . . 3 ⊢ ((𝐶 ∈ (∞Met‘𝑋) ∧ 𝐷 ∈ (∞Met‘𝑋)) → (𝐽 ⊆ 𝐾 ↔ ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟))) |
21 | 17, 19, 20 | syl2anc 693 | . 2 ⊢ (𝜑 → (𝐽 ⊆ 𝐾 ↔ ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟))) |
22 | 15, 21 | mpbird 247 | 1 ⊢ (𝜑 → 𝐽 ⊆ 𝐾) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 196 ∧ wa 384 = wceq 1483 ∈ wcel 1990 ∀wral 2912 ∃wrex 2913 ⊆ wss 3574 class class class wbr 4653 ‘cfv 5888 (class class class)co 6650 · cmul 9941 ≤ cle 10075 / cdiv 10684 ℝ+crp 11832 ∞Metcxmt 19731 Metcme 19732 ballcbl 19733 MetOpencmopn 19736 |
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-8 1992 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-pow 4843 ax-pr 4906 ax-un 6949 ax-cnex 9992 ax-resscn 9993 ax-1cn 9994 ax-icn 9995 ax-addcl 9996 ax-addrcl 9997 ax-mulcl 9998 ax-mulrcl 9999 ax-mulcom 10000 ax-addass 10001 ax-mulass 10002 ax-distr 10003 ax-i2m1 10004 ax-1ne0 10005 ax-1rid 10006 ax-rnegex 10007 ax-rrecex 10008 ax-cnre 10009 ax-pre-lttri 10010 ax-pre-lttrn 10011 ax-pre-ltadd 10012 ax-pre-mulgt0 10013 ax-pre-sup 10014 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-3or 1038 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-ne 2795 df-nel 2898 df-ral 2917 df-rex 2918 df-reu 2919 df-rmo 2920 df-rab 2921 df-v 3202 df-sbc 3436 df-csb 3534 df-dif 3577 df-un 3579 df-in 3581 df-ss 3588 df-pss 3590 df-nul 3916 df-if 4087 df-pw 4160 df-sn 4178 df-pr 4180 df-tp 4182 df-op 4184 df-uni 4437 df-iun 4522 df-br 4654 df-opab 4713 df-mpt 4730 df-tr 4753 df-id 5024 df-eprel 5029 df-po 5035 df-so 5036 df-fr 5073 df-we 5075 df-xp 5120 df-rel 5121 df-cnv 5122 df-co 5123 df-dm 5124 df-rn 5125 df-res 5126 df-ima 5127 df-pred 5680 df-ord 5726 df-on 5727 df-lim 5728 df-suc 5729 df-iota 5851 df-fun 5890 df-fn 5891 df-f 5892 df-f1 5893 df-fo 5894 df-f1o 5895 df-fv 5896 df-riota 6611 df-ov 6653 df-oprab 6654 df-mpt2 6655 df-om 7066 df-1st 7168 df-2nd 7169 df-wrecs 7407 df-recs 7468 df-rdg 7506 df-er 7742 df-map 7859 df-en 7956 df-dom 7957 df-sdom 7958 df-sup 8348 df-inf 8349 df-pnf 10076 df-mnf 10077 df-xr 10078 df-ltxr 10079 df-le 10080 df-sub 10268 df-neg 10269 df-div 10685 df-nn 11021 df-2 11079 df-n0 11293 df-z 11378 df-uz 11688 df-q 11789 df-rp 11833 df-xneg 11946 df-xadd 11947 df-xmul 11948 df-topgen 16104 df-psmet 19738 df-xmet 19739 df-met 19740 df-bl 19741 df-mopn 19742 df-bases 20750 |
This theorem is referenced by: equivcmet 23114 |
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