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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 487 | . . . . 5 ⊢ ((𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+) → 𝑟 ∈ ℝ+) | |
2 | metss2.3 | . . . . 5 ⊢ (𝜑 → 𝑅 ∈ ℝ+) | |
3 | rpdivcl 12417 | . . . . 5 ⊢ ((𝑟 ∈ ℝ+ ∧ 𝑅 ∈ ℝ+) → (𝑟 / 𝑅) ∈ ℝ+) | |
4 | 1, 2, 3 | syl2anr 598 | . . . 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 23123 | . . . 4 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟)) |
11 | oveq2 7166 | . . . . . 6 ⊢ (𝑠 = (𝑟 / 𝑅) → (𝑥(ball‘𝐷)𝑠) = (𝑥(ball‘𝐷)(𝑟 / 𝑅))) | |
12 | 11 | sseq1d 4000 | . . . . 5 ⊢ (𝑠 = (𝑟 / 𝑅) → ((𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟) ↔ (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟))) |
13 | 12 | rspcev 3625 | . . . 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 586 | . . 3 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
15 | 14 | ralrimivva 3193 | . 2 ⊢ (𝜑 → ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
16 | metxmet 22946 | . . . 4 ⊢ (𝐶 ∈ (Met‘𝑋) → 𝐶 ∈ (∞Met‘𝑋)) | |
17 | 7, 16 | syl 17 | . . 3 ⊢ (𝜑 → 𝐶 ∈ (∞Met‘𝑋)) |
18 | metxmet 22946 | . . . 4 ⊢ (𝐷 ∈ (Met‘𝑋) → 𝐷 ∈ (∞Met‘𝑋)) | |
19 | 8, 18 | syl 17 | . . 3 ⊢ (𝜑 → 𝐷 ∈ (∞Met‘𝑋)) |
20 | 5, 6 | metss 23120 | . . 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 586 | . 2 ⊢ (𝜑 → (𝐽 ⊆ 𝐾 ↔ ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟))) |
22 | 15, 21 | mpbird 259 | 1 ⊢ (𝜑 → 𝐽 ⊆ 𝐾) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1537 ∈ wcel 2114 ∀wral 3140 ∃wrex 3141 ⊆ wss 3938 class class class wbr 5068 ‘cfv 6357 (class class class)co 7158 · cmul 10544 ≤ cle 10678 / cdiv 11299 ℝ+crp 12392 ∞Metcxmet 20532 Metcmet 20533 ballcbl 20534 MetOpencmopn 20537 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1796 ax-4 1810 ax-5 1911 ax-6 1970 ax-7 2015 ax-8 2116 ax-9 2124 ax-10 2145 ax-11 2161 ax-12 2177 ax-ext 2795 ax-sep 5205 ax-nul 5212 ax-pow 5268 ax-pr 5332 ax-un 7463 ax-cnex 10595 ax-resscn 10596 ax-1cn 10597 ax-icn 10598 ax-addcl 10599 ax-addrcl 10600 ax-mulcl 10601 ax-mulrcl 10602 ax-mulcom 10603 ax-addass 10604 ax-mulass 10605 ax-distr 10606 ax-i2m1 10607 ax-1ne0 10608 ax-1rid 10609 ax-rnegex 10610 ax-rrecex 10611 ax-cnre 10612 ax-pre-lttri 10613 ax-pre-lttrn 10614 ax-pre-ltadd 10615 ax-pre-mulgt0 10616 ax-pre-sup 10617 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3or 1084 df-3an 1085 df-tru 1540 df-ex 1781 df-nf 1785 df-sb 2070 df-mo 2622 df-eu 2654 df-clab 2802 df-cleq 2816 df-clel 2895 df-nfc 2965 df-ne 3019 df-nel 3126 df-ral 3145 df-rex 3146 df-reu 3147 df-rmo 3148 df-rab 3149 df-v 3498 df-sbc 3775 df-csb 3886 df-dif 3941 df-un 3943 df-in 3945 df-ss 3954 df-pss 3956 df-nul 4294 df-if 4470 df-pw 4543 df-sn 4570 df-pr 4572 df-tp 4574 df-op 4576 df-uni 4841 df-iun 4923 df-br 5069 df-opab 5131 df-mpt 5149 df-tr 5175 df-id 5462 df-eprel 5467 df-po 5476 df-so 5477 df-fr 5516 df-we 5518 df-xp 5563 df-rel 5564 df-cnv 5565 df-co 5566 df-dm 5567 df-rn 5568 df-res 5569 df-ima 5570 df-pred 6150 df-ord 6196 df-on 6197 df-lim 6198 df-suc 6199 df-iota 6316 df-fun 6359 df-fn 6360 df-f 6361 df-f1 6362 df-fo 6363 df-f1o 6364 df-fv 6365 df-riota 7116 df-ov 7161 df-oprab 7162 df-mpo 7163 df-om 7583 df-1st 7691 df-2nd 7692 df-wrecs 7949 df-recs 8010 df-rdg 8048 df-er 8291 df-map 8410 df-en 8512 df-dom 8513 df-sdom 8514 df-sup 8908 df-inf 8909 df-pnf 10679 df-mnf 10680 df-xr 10681 df-ltxr 10682 df-le 10683 df-sub 10874 df-neg 10875 df-div 11300 df-nn 11641 df-2 11703 df-n0 11901 df-z 11985 df-uz 12247 df-q 12352 df-rp 12393 df-xneg 12510 df-xadd 12511 df-xmul 12512 df-topgen 16719 df-psmet 20539 df-xmet 20540 df-met 20541 df-bl 20542 df-mopn 20543 df-bases 21556 |
This theorem is referenced by: equivcmet 23922 |
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