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Mirrors > Home > ILE Home > Th. List > minabs | GIF version |
Description: The minimum of two real numbers in terms of absolute value. (Contributed by Jim Kingdon, 15-May-2023.) |
Ref | Expression |
---|---|
minabs | ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → inf({𝐴, 𝐵}, ℝ, < ) = (((𝐴 + 𝐵) − (abs‘(𝐴 − 𝐵))) / 2)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | minmax 11204 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → inf({𝐴, 𝐵}, ℝ, < ) = -sup({-𝐴, -𝐵}, ℝ, < )) | |
2 | renegcl 8192 | . . . . 5 ⊢ (𝐴 ∈ ℝ → -𝐴 ∈ ℝ) | |
3 | renegcl 8192 | . . . . 5 ⊢ (𝐵 ∈ ℝ → -𝐵 ∈ ℝ) | |
4 | maxabs 11184 | . . . . 5 ⊢ ((-𝐴 ∈ ℝ ∧ -𝐵 ∈ ℝ) → sup({-𝐴, -𝐵}, ℝ, < ) = (((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2)) | |
5 | 2, 3, 4 | syl2an 289 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → sup({-𝐴, -𝐵}, ℝ, < ) = (((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2)) |
6 | 5 | negeqd 8126 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -sup({-𝐴, -𝐵}, ℝ, < ) = -(((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2)) |
7 | 1, 6 | eqtrd 2208 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → inf({𝐴, 𝐵}, ℝ, < ) = -(((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2)) |
8 | simpl 109 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 𝐴 ∈ ℝ) | |
9 | 8 | recnd 7960 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 𝐴 ∈ ℂ) |
10 | 9 | negcld 8229 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -𝐴 ∈ ℂ) |
11 | simpr 110 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 𝐵 ∈ ℝ) | |
12 | 11 | recnd 7960 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 𝐵 ∈ ℂ) |
13 | 12 | negcld 8229 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -𝐵 ∈ ℂ) |
14 | 10, 13 | addcld 7951 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (-𝐴 + -𝐵) ∈ ℂ) |
15 | 10, 13 | subcld 8242 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (-𝐴 − -𝐵) ∈ ℂ) |
16 | 15 | abscld 11156 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (abs‘(-𝐴 − -𝐵)) ∈ ℝ) |
17 | 16 | recnd 7960 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (abs‘(-𝐴 − -𝐵)) ∈ ℂ) |
18 | 14, 17 | addcld 7951 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → ((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) ∈ ℂ) |
19 | 2cnd 8963 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 2 ∈ ℂ) | |
20 | 2ap0 8983 | . . . 4 ⊢ 2 # 0 | |
21 | 20 | a1i 9 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → 2 # 0) |
22 | 18, 19, 21 | divnegapd 8732 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -(((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2) = (-((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2)) |
23 | 14, 17 | negdi2d 8256 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) = (-(-𝐴 + -𝐵) − (abs‘(-𝐴 − -𝐵)))) |
24 | 10, 13 | negdid 8255 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -(-𝐴 + -𝐵) = (--𝐴 + --𝐵)) |
25 | 9 | negnegd 8233 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → --𝐴 = 𝐴) |
26 | 12 | negnegd 8233 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → --𝐵 = 𝐵) |
27 | 25, 26 | oveq12d 5883 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (--𝐴 + --𝐵) = (𝐴 + 𝐵)) |
28 | 24, 27 | eqtrd 2208 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -(-𝐴 + -𝐵) = (𝐴 + 𝐵)) |
29 | 9, 12 | neg2subd 8259 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (-𝐴 − -𝐵) = (𝐵 − 𝐴)) |
30 | 29 | fveq2d 5511 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (abs‘(-𝐴 − -𝐵)) = (abs‘(𝐵 − 𝐴))) |
31 | 9, 12 | abssubd 11168 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (abs‘(𝐴 − 𝐵)) = (abs‘(𝐵 − 𝐴))) |
32 | 30, 31 | eqtr4d 2211 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (abs‘(-𝐴 − -𝐵)) = (abs‘(𝐴 − 𝐵))) |
33 | 28, 32 | oveq12d 5883 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (-(-𝐴 + -𝐵) − (abs‘(-𝐴 − -𝐵))) = ((𝐴 + 𝐵) − (abs‘(𝐴 − 𝐵)))) |
34 | 23, 33 | eqtrd 2208 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → -((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) = ((𝐴 + 𝐵) − (abs‘(𝐴 − 𝐵)))) |
35 | 34 | oveq1d 5880 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (-((-𝐴 + -𝐵) + (abs‘(-𝐴 − -𝐵))) / 2) = (((𝐴 + 𝐵) − (abs‘(𝐴 − 𝐵))) / 2)) |
36 | 7, 22, 35 | 3eqtrd 2212 | 1 ⊢ ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → inf({𝐴, 𝐵}, ℝ, < ) = (((𝐴 + 𝐵) − (abs‘(𝐴 − 𝐵))) / 2)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 104 = wceq 1353 ∈ wcel 2146 {cpr 3590 class class class wbr 3998 ‘cfv 5208 (class class class)co 5865 supcsup 6971 infcinf 6972 ℝcr 7785 0cc0 7786 + caddc 7789 < clt 7966 − cmin 8102 -cneg 8103 # cap 8512 / cdiv 8601 2c2 8941 abscabs 10972 |
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 1445 ax-7 1446 ax-gen 1447 ax-ie1 1491 ax-ie2 1492 ax-8 1502 ax-10 1503 ax-11 1504 ax-i12 1505 ax-bndl 1507 ax-4 1508 ax-17 1524 ax-i9 1528 ax-ial 1532 ax-i5r 1533 ax-13 2148 ax-14 2149 ax-ext 2157 ax-coll 4113 ax-sep 4116 ax-nul 4124 ax-pow 4169 ax-pr 4203 ax-un 4427 ax-setind 4530 ax-iinf 4581 ax-cnex 7877 ax-resscn 7878 ax-1cn 7879 ax-1re 7880 ax-icn 7881 ax-addcl 7882 ax-addrcl 7883 ax-mulcl 7884 ax-mulrcl 7885 ax-addcom 7886 ax-mulcom 7887 ax-addass 7888 ax-mulass 7889 ax-distr 7890 ax-i2m1 7891 ax-0lt1 7892 ax-1rid 7893 ax-0id 7894 ax-rnegex 7895 ax-precex 7896 ax-cnre 7897 ax-pre-ltirr 7898 ax-pre-ltwlin 7899 ax-pre-lttrn 7900 ax-pre-apti 7901 ax-pre-ltadd 7902 ax-pre-mulgt0 7903 ax-pre-mulext 7904 ax-arch 7905 ax-caucvg 7906 |
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 1459 df-sb 1761 df-eu 2027 df-mo 2028 df-clab 2162 df-cleq 2168 df-clel 2171 df-nfc 2306 df-ne 2346 df-nel 2441 df-ral 2458 df-rex 2459 df-reu 2460 df-rmo 2461 df-rab 2462 df-v 2737 df-sbc 2961 df-csb 3056 df-dif 3129 df-un 3131 df-in 3133 df-ss 3140 df-nul 3421 df-if 3533 df-pw 3574 df-sn 3595 df-pr 3596 df-op 3598 df-uni 3806 df-int 3841 df-iun 3884 df-br 3999 df-opab 4060 df-mpt 4061 df-tr 4097 df-id 4287 df-po 4290 df-iso 4291 df-iord 4360 df-on 4362 df-ilim 4363 df-suc 4365 df-iom 4584 df-xp 4626 df-rel 4627 df-cnv 4628 df-co 4629 df-dm 4630 df-rn 4631 df-res 4632 df-ima 4633 df-iota 5170 df-fun 5210 df-fn 5211 df-f 5212 df-f1 5213 df-fo 5214 df-f1o 5215 df-fv 5216 df-isom 5217 df-riota 5821 df-ov 5868 df-oprab 5869 df-mpo 5870 df-1st 6131 df-2nd 6132 df-recs 6296 df-frec 6382 df-sup 6973 df-inf 6974 df-pnf 7968 df-mnf 7969 df-xr 7970 df-ltxr 7971 df-le 7972 df-sub 8104 df-neg 8105 df-reap 8506 df-ap 8513 df-div 8602 df-inn 8891 df-2 8949 df-3 8950 df-4 8951 df-n0 9148 df-z 9225 df-uz 9500 df-rp 9623 df-seqfrec 10414 df-exp 10488 df-cj 10817 df-re 10818 df-im 10819 df-rsqrt 10973 df-abs 10974 |
This theorem is referenced by: bdtri 11214 |
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