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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 476 | . . . . 5 ⊢ ((𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+) → 𝑟 ∈ ℝ+) | |
2 | metss2.3 | . . . . 5 ⊢ (𝜑 → 𝑅 ∈ ℝ+) | |
3 | rpdivcl 11732 | . . . . 5 ⊢ ((𝑟 ∈ ℝ+ ∧ 𝑅 ∈ ℝ+) → (𝑟 / 𝑅) ∈ ℝ+) | |
4 | 1, 2, 3 | syl2anr 494 | . . . 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 22126 | . . . 4 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟)) |
11 | oveq2 6557 | . . . . . 6 ⊢ (𝑠 = (𝑟 / 𝑅) → (𝑥(ball‘𝐷)𝑠) = (𝑥(ball‘𝐷)(𝑟 / 𝑅))) | |
12 | 11 | sseq1d 3595 | . . . . 5 ⊢ (𝑠 = (𝑟 / 𝑅) → ((𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟) ↔ (𝑥(ball‘𝐷)(𝑟 / 𝑅)) ⊆ (𝑥(ball‘𝐶)𝑟))) |
13 | 12 | rspcev 3282 | . . . 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 691 | . . 3 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑋 ∧ 𝑟 ∈ ℝ+)) → ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
15 | 14 | ralrimivva 2954 | . 2 ⊢ (𝜑 → ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟)) |
16 | metxmet 21949 | . . . 4 ⊢ (𝐶 ∈ (Met‘𝑋) → 𝐶 ∈ (∞Met‘𝑋)) | |
17 | 7, 16 | syl 17 | . . 3 ⊢ (𝜑 → 𝐶 ∈ (∞Met‘𝑋)) |
18 | metxmet 21949 | . . . 4 ⊢ (𝐷 ∈ (Met‘𝑋) → 𝐷 ∈ (∞Met‘𝑋)) | |
19 | 8, 18 | syl 17 | . . 3 ⊢ (𝜑 → 𝐷 ∈ (∞Met‘𝑋)) |
20 | 5, 6 | metss 22123 | . . 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 691 | . 2 ⊢ (𝜑 → (𝐽 ⊆ 𝐾 ↔ ∀𝑥 ∈ 𝑋 ∀𝑟 ∈ ℝ+ ∃𝑠 ∈ ℝ+ (𝑥(ball‘𝐷)𝑠) ⊆ (𝑥(ball‘𝐶)𝑟))) |
22 | 15, 21 | mpbird 246 | 1 ⊢ (𝜑 → 𝐽 ⊆ 𝐾) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 195 ∧ wa 383 = wceq 1475 ∈ wcel 1977 ∀wral 2896 ∃wrex 2897 ⊆ wss 3540 class class class wbr 4583 ‘cfv 5804 (class class class)co 6549 · cmul 9820 ≤ cle 9954 / cdiv 10563 ℝ+crp 11708 ∞Metcxmt 19552 Metcme 19553 ballcbl 19554 MetOpencmopn 19557 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1713 ax-4 1728 ax-5 1827 ax-6 1875 ax-7 1922 ax-8 1979 ax-9 1986 ax-10 2006 ax-11 2021 ax-12 2034 ax-13 2234 ax-ext 2590 ax-sep 4709 ax-nul 4717 ax-pow 4769 ax-pr 4833 ax-un 6847 ax-cnex 9871 ax-resscn 9872 ax-1cn 9873 ax-icn 9874 ax-addcl 9875 ax-addrcl 9876 ax-mulcl 9877 ax-mulrcl 9878 ax-mulcom 9879 ax-addass 9880 ax-mulass 9881 ax-distr 9882 ax-i2m1 9883 ax-1ne0 9884 ax-1rid 9885 ax-rnegex 9886 ax-rrecex 9887 ax-cnre 9888 ax-pre-lttri 9889 ax-pre-lttrn 9890 ax-pre-ltadd 9891 ax-pre-mulgt0 9892 ax-pre-sup 9893 |
This theorem depends on definitions: df-bi 196 df-or 384 df-an 385 df-3or 1032 df-3an 1033 df-tru 1478 df-ex 1696 df-nf 1701 df-sb 1868 df-eu 2462 df-mo 2463 df-clab 2597 df-cleq 2603 df-clel 2606 df-nfc 2740 df-ne 2782 df-nel 2783 df-ral 2901 df-rex 2902 df-reu 2903 df-rmo 2904 df-rab 2905 df-v 3175 df-sbc 3403 df-csb 3500 df-dif 3543 df-un 3545 df-in 3547 df-ss 3554 df-pss 3556 df-nul 3875 df-if 4037 df-pw 4110 df-sn 4126 df-pr 4128 df-tp 4130 df-op 4132 df-uni 4373 df-iun 4457 df-br 4584 df-opab 4644 df-mpt 4645 df-tr 4681 df-eprel 4949 df-id 4953 df-po 4959 df-so 4960 df-fr 4997 df-we 4999 df-xp 5044 df-rel 5045 df-cnv 5046 df-co 5047 df-dm 5048 df-rn 5049 df-res 5050 df-ima 5051 df-pred 5597 df-ord 5643 df-on 5644 df-lim 5645 df-suc 5646 df-iota 5768 df-fun 5806 df-fn 5807 df-f 5808 df-f1 5809 df-fo 5810 df-f1o 5811 df-fv 5812 df-riota 6511 df-ov 6552 df-oprab 6553 df-mpt2 6554 df-om 6958 df-1st 7059 df-2nd 7060 df-wrecs 7294 df-recs 7355 df-rdg 7393 df-er 7629 df-map 7746 df-en 7842 df-dom 7843 df-sdom 7844 df-sup 8231 df-inf 8232 df-pnf 9955 df-mnf 9956 df-xr 9957 df-ltxr 9958 df-le 9959 df-sub 10147 df-neg 10148 df-div 10564 df-nn 10898 df-2 10956 df-n0 11170 df-z 11255 df-uz 11564 df-q 11665 df-rp 11709 df-xneg 11822 df-xadd 11823 df-xmul 11824 df-topgen 15927 df-psmet 19559 df-xmet 19560 df-met 19561 df-bl 19562 df-mopn 19563 df-bases 20522 |
This theorem is referenced by: equivcmet 22922 |
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