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Mirrors > Home > ILE Home > Th. List > psmetge0 | GIF version |
Description: The distance function of a pseudometric space is nonnegative. (Contributed by Thierry Arnoux, 7-Feb-2018.) (Revised by Jim Kingdon, 19-Apr-2023.) |
Ref | Expression |
---|---|
psmetge0 | ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 0 ≤ (𝐴𝐷𝐵)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0xr 7998 | . . . 4 ⊢ 0 ∈ ℝ* | |
2 | xaddid1 9856 | . . . 4 ⊢ (0 ∈ ℝ* → (0 +𝑒 0) = 0) | |
3 | 1, 2 | ax-mp 5 | . . 3 ⊢ (0 +𝑒 0) = 0 |
4 | psmet0 13669 | . . . . 5 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐵 ∈ 𝑋) → (𝐵𝐷𝐵) = 0) | |
5 | 4 | 3adant2 1016 | . . . 4 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐵𝐷𝐵) = 0) |
6 | simp1 997 | . . . . 5 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐷 ∈ (PsMet‘𝑋)) | |
7 | simp2 998 | . . . . 5 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐴 ∈ 𝑋) | |
8 | simp3 999 | . . . . 5 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 𝐵 ∈ 𝑋) | |
9 | psmettri2 13670 | . . . . 5 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ (𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋)) → (𝐵𝐷𝐵) ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵))) | |
10 | 6, 7, 8, 8, 9 | syl13anc 1240 | . . . 4 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐵𝐷𝐵) ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵))) |
11 | 5, 10 | eqbrtrrd 4025 | . . 3 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 0 ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵))) |
12 | 3, 11 | eqbrtrid 4036 | . 2 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (0 +𝑒 0) ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵))) |
13 | psmetcl 13668 | . . 3 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (𝐴𝐷𝐵) ∈ ℝ*) | |
14 | xleaddadd 9881 | . . 3 ⊢ ((0 ∈ ℝ* ∧ (𝐴𝐷𝐵) ∈ ℝ*) → (0 ≤ (𝐴𝐷𝐵) ↔ (0 +𝑒 0) ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵)))) | |
15 | 1, 13, 14 | sylancr 414 | . 2 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → (0 ≤ (𝐴𝐷𝐵) ↔ (0 +𝑒 0) ≤ ((𝐴𝐷𝐵) +𝑒 (𝐴𝐷𝐵)))) |
16 | 12, 15 | mpbird 167 | 1 ⊢ ((𝐷 ∈ (PsMet‘𝑋) ∧ 𝐴 ∈ 𝑋 ∧ 𝐵 ∈ 𝑋) → 0 ≤ (𝐴𝐷𝐵)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 105 ∧ w3a 978 = wceq 1353 ∈ wcel 2148 class class class wbr 4001 ‘cfv 5213 (class class class)co 5870 0cc0 7806 ℝ*cxr 7985 ≤ cle 7987 +𝑒 cxad 9764 PsMetcpsmet 13279 |
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 614 ax-in2 615 ax-io 709 ax-5 1447 ax-7 1448 ax-gen 1449 ax-ie1 1493 ax-ie2 1494 ax-8 1504 ax-10 1505 ax-11 1506 ax-i12 1507 ax-bndl 1509 ax-4 1510 ax-17 1526 ax-i9 1530 ax-ial 1534 ax-i5r 1535 ax-13 2150 ax-14 2151 ax-ext 2159 ax-sep 4119 ax-pow 4172 ax-pr 4207 ax-un 4431 ax-setind 4534 ax-cnex 7897 ax-resscn 7898 ax-1cn 7899 ax-1re 7900 ax-icn 7901 ax-addcl 7902 ax-addrcl 7903 ax-mulcl 7904 ax-mulrcl 7905 ax-addcom 7906 ax-mulcom 7907 ax-addass 7908 ax-mulass 7909 ax-distr 7910 ax-i2m1 7911 ax-0lt1 7912 ax-1rid 7913 ax-0id 7914 ax-rnegex 7915 ax-precex 7916 ax-cnre 7917 ax-pre-ltirr 7918 ax-pre-lttrn 7920 ax-pre-ltadd 7922 ax-pre-mulgt0 7923 |
This theorem depends on definitions: df-bi 117 df-dc 835 df-3or 979 df-3an 980 df-tru 1356 df-fal 1359 df-nf 1461 df-sb 1763 df-eu 2029 df-mo 2030 df-clab 2164 df-cleq 2170 df-clel 2173 df-nfc 2308 df-ne 2348 df-nel 2443 df-ral 2460 df-rex 2461 df-reu 2462 df-rab 2464 df-v 2739 df-sbc 2963 df-csb 3058 df-dif 3131 df-un 3133 df-in 3135 df-ss 3142 df-if 3535 df-pw 3577 df-sn 3598 df-pr 3599 df-op 3601 df-uni 3809 df-iun 3887 df-br 4002 df-opab 4063 df-mpt 4064 df-id 4291 df-xp 4630 df-rel 4631 df-cnv 4632 df-co 4633 df-dm 4634 df-rn 4635 df-res 4636 df-ima 4637 df-iota 5175 df-fun 5215 df-fn 5216 df-f 5217 df-fv 5221 df-riota 5826 df-ov 5873 df-oprab 5874 df-mpo 5875 df-1st 6136 df-2nd 6137 df-map 6645 df-pnf 7988 df-mnf 7989 df-xr 7990 df-ltxr 7991 df-le 7992 df-sub 8124 df-neg 8125 df-2 8972 df-xadd 9767 df-psmet 13287 |
This theorem is referenced by: psmetxrge0 13674 psmetlecl 13676 distspace 13677 xblpnfps 13740 xblss2ps 13746 |
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