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Theorem xaddval 9654
Description: Value of the extended real addition operation. (Contributed by Mario Carneiro, 20-Aug-2015.)
Assertion
Ref Expression
xaddval ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → (𝐴 +𝑒 𝐵) = if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))))

Proof of Theorem xaddval
Dummy variables 𝑥 𝑦 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 0xr 7832 . . . . . 6 0 ∈ ℝ*
21a1i 9 . . . . 5 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → 0 ∈ ℝ*)
3 pnfxr 7838 . . . . . 6 +∞ ∈ ℝ*
43a1i 9 . . . . 5 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → +∞ ∈ ℝ*)
5 xrmnfdc 9652 . . . . . 6 (𝐵 ∈ ℝ*DECID 𝐵 = -∞)
65adantl 275 . . . . 5 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → DECID 𝐵 = -∞)
72, 4, 6ifcldcd 3508 . . . 4 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → if(𝐵 = -∞, 0, +∞) ∈ ℝ*)
87adantr 274 . . 3 (((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ 𝐴 = +∞) → if(𝐵 = -∞, 0, +∞) ∈ ℝ*)
9 mnfxr 7842 . . . . . . 7 -∞ ∈ ℝ*
109a1i 9 . . . . . 6 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → -∞ ∈ ℝ*)
11 xrpnfdc 9651 . . . . . . 7 (𝐵 ∈ ℝ*DECID 𝐵 = +∞)
1211adantl 275 . . . . . 6 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → DECID 𝐵 = +∞)
132, 10, 12ifcldcd 3508 . . . . 5 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → if(𝐵 = +∞, 0, -∞) ∈ ℝ*)
1413ad2antrr 480 . . . 4 ((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ 𝐴 = -∞) → if(𝐵 = +∞, 0, -∞) ∈ ℝ*)
153a1i 9 . . . . 5 (((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ 𝐵 = +∞) → +∞ ∈ ℝ*)
169a1i 9 . . . . . 6 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ 𝐵 = -∞) → -∞ ∈ ℝ*)
17 simp-4r 532 . . . . . . . . 9 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → ¬ 𝐴 = +∞)
18 simpl 108 . . . . . . . . . . 11 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → 𝐴 ∈ ℝ*)
1918ad4antr 486 . . . . . . . . . 10 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐴 ∈ ℝ*)
20 simpllr 524 . . . . . . . . . . 11 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → ¬ 𝐴 = -∞)
2120neqned 2316 . . . . . . . . . 10 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐴 ≠ -∞)
22 xrnemnf 9590 . . . . . . . . . . 11 ((𝐴 ∈ ℝ*𝐴 ≠ -∞) ↔ (𝐴 ∈ ℝ ∨ 𝐴 = +∞))
2322biimpi 119 . . . . . . . . . 10 ((𝐴 ∈ ℝ*𝐴 ≠ -∞) → (𝐴 ∈ ℝ ∨ 𝐴 = +∞))
2419, 21, 23syl2anc 409 . . . . . . . . 9 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → (𝐴 ∈ ℝ ∨ 𝐴 = +∞))
2517, 24ecased 1328 . . . . . . . 8 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐴 ∈ ℝ)
26 simplr 520 . . . . . . . . 9 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → ¬ 𝐵 = +∞)
27 simpr 109 . . . . . . . . . . 11 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → 𝐵 ∈ ℝ*)
2827ad4antr 486 . . . . . . . . . 10 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐵 ∈ ℝ*)
29 simpr 109 . . . . . . . . . . 11 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → ¬ 𝐵 = -∞)
3029neqned 2316 . . . . . . . . . 10 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐵 ≠ -∞)
31 xrnemnf 9590 . . . . . . . . . . 11 ((𝐵 ∈ ℝ*𝐵 ≠ -∞) ↔ (𝐵 ∈ ℝ ∨ 𝐵 = +∞))
3231biimpi 119 . . . . . . . . . 10 ((𝐵 ∈ ℝ*𝐵 ≠ -∞) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞))
3328, 30, 32syl2anc 409 . . . . . . . . 9 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → (𝐵 ∈ ℝ ∨ 𝐵 = +∞))
3426, 33ecased 1328 . . . . . . . 8 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → 𝐵 ∈ ℝ)
3525, 34readdcld 7815 . . . . . . 7 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → (𝐴 + 𝐵) ∈ ℝ)
3635rexrd 7835 . . . . . 6 ((((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) ∧ ¬ 𝐵 = -∞) → (𝐴 + 𝐵) ∈ ℝ*)
376ad3antrrr 484 . . . . . 6 (((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) → DECID 𝐵 = -∞)
3816, 36, 37ifcldadc 3502 . . . . 5 (((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) ∧ ¬ 𝐵 = +∞) → if(𝐵 = -∞, -∞, (𝐴 + 𝐵)) ∈ ℝ*)
3912ad2antrr 480 . . . . 5 ((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) → DECID 𝐵 = +∞)
4015, 38, 39ifcldadc 3502 . . . 4 ((((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) ∧ ¬ 𝐴 = -∞) → if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))) ∈ ℝ*)
41 xrmnfdc 9652 . . . . 5 (𝐴 ∈ ℝ*DECID 𝐴 = -∞)
4241ad2antrr 480 . . . 4 (((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) → DECID 𝐴 = -∞)
4314, 40, 42ifcldadc 3502 . . 3 (((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) ∧ ¬ 𝐴 = +∞) → if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵)))) ∈ ℝ*)
44 xrpnfdc 9651 . . . 4 (𝐴 ∈ ℝ*DECID 𝐴 = +∞)
4544adantr 274 . . 3 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → DECID 𝐴 = +∞)
468, 43, 45ifcldadc 3502 . 2 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))) ∈ ℝ*)
47 simpl 108 . . . . 5 ((𝑥 = 𝐴𝑦 = 𝐵) → 𝑥 = 𝐴)
4847eqeq1d 2149 . . . 4 ((𝑥 = 𝐴𝑦 = 𝐵) → (𝑥 = +∞ ↔ 𝐴 = +∞))
49 simpr 109 . . . . . 6 ((𝑥 = 𝐴𝑦 = 𝐵) → 𝑦 = 𝐵)
5049eqeq1d 2149 . . . . 5 ((𝑥 = 𝐴𝑦 = 𝐵) → (𝑦 = -∞ ↔ 𝐵 = -∞))
5150ifbid 3494 . . . 4 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑦 = -∞, 0, +∞) = if(𝐵 = -∞, 0, +∞))
5247eqeq1d 2149 . . . . 5 ((𝑥 = 𝐴𝑦 = 𝐵) → (𝑥 = -∞ ↔ 𝐴 = -∞))
5349eqeq1d 2149 . . . . . 6 ((𝑥 = 𝐴𝑦 = 𝐵) → (𝑦 = +∞ ↔ 𝐵 = +∞))
5453ifbid 3494 . . . . 5 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑦 = +∞, 0, -∞) = if(𝐵 = +∞, 0, -∞))
55 oveq12 5787 . . . . . . 7 ((𝑥 = 𝐴𝑦 = 𝐵) → (𝑥 + 𝑦) = (𝐴 + 𝐵))
5650, 55ifbieq2d 3497 . . . . . 6 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑦 = -∞, -∞, (𝑥 + 𝑦)) = if(𝐵 = -∞, -∞, (𝐴 + 𝐵)))
5753, 56ifbieq2d 3497 . . . . 5 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑦 = +∞, +∞, if(𝑦 = -∞, -∞, (𝑥 + 𝑦))) = if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))
5852, 54, 57ifbieq12d 3499 . . . 4 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑥 = -∞, if(𝑦 = +∞, 0, -∞), if(𝑦 = +∞, +∞, if(𝑦 = -∞, -∞, (𝑥 + 𝑦)))) = if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵)))))
5948, 51, 58ifbieq12d 3499 . . 3 ((𝑥 = 𝐴𝑦 = 𝐵) → if(𝑥 = +∞, if(𝑦 = -∞, 0, +∞), if(𝑥 = -∞, if(𝑦 = +∞, 0, -∞), if(𝑦 = +∞, +∞, if(𝑦 = -∞, -∞, (𝑥 + 𝑦))))) = if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))))
60 df-xadd 9586 . . 3 +𝑒 = (𝑥 ∈ ℝ*, 𝑦 ∈ ℝ* ↦ if(𝑥 = +∞, if(𝑦 = -∞, 0, +∞), if(𝑥 = -∞, if(𝑦 = +∞, 0, -∞), if(𝑦 = +∞, +∞, if(𝑦 = -∞, -∞, (𝑥 + 𝑦))))))
6159, 60ovmpoga 5904 . 2 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ* ∧ if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))) ∈ ℝ*) → (𝐴 +𝑒 𝐵) = if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))))
6246, 61mpd3an3 1317 1 ((𝐴 ∈ ℝ*𝐵 ∈ ℝ*) → (𝐴 +𝑒 𝐵) = if(𝐴 = +∞, if(𝐵 = -∞, 0, +∞), if(𝐴 = -∞, if(𝐵 = +∞, 0, -∞), if(𝐵 = +∞, +∞, if(𝐵 = -∞, -∞, (𝐴 + 𝐵))))))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4  wa 103  wo 698  DECID wdc 820   = wceq 1332  wcel 1481  wne 2309  ifcif 3475  (class class class)co 5778  cr 7639  0cc0 7640   + caddc 7643  +∞cpnf 7817  -∞cmnf 7818  *cxr 7819   +𝑒 cxad 9583
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-in1 604  ax-in2 605  ax-io 699  ax-5 1424  ax-7 1425  ax-gen 1426  ax-ie1 1470  ax-ie2 1471  ax-8 1483  ax-10 1484  ax-11 1485  ax-i12 1486  ax-bndl 1487  ax-4 1488  ax-13 1492  ax-14 1493  ax-17 1507  ax-i9 1511  ax-ial 1515  ax-i5r 1516  ax-ext 2122  ax-sep 4050  ax-pow 4102  ax-pr 4135  ax-un 4359  ax-setind 4456  ax-cnex 7731  ax-resscn 7732  ax-1re 7734  ax-addrcl 7737  ax-rnegex 7749
This theorem depends on definitions:  df-bi 116  df-dc 821  df-3or 964  df-3an 965  df-tru 1335  df-fal 1338  df-nf 1438  df-sb 1737  df-eu 2003  df-mo 2004  df-clab 2127  df-cleq 2133  df-clel 2136  df-nfc 2271  df-ne 2310  df-nel 2405  df-ral 2422  df-rex 2423  df-rab 2426  df-v 2689  df-sbc 2911  df-dif 3074  df-un 3076  df-in 3078  df-ss 3085  df-if 3476  df-pw 3513  df-sn 3534  df-pr 3535  df-op 3537  df-uni 3741  df-br 3934  df-opab 3994  df-id 4219  df-xp 4549  df-rel 4550  df-cnv 4551  df-co 4552  df-dm 4553  df-iota 5092  df-fun 5129  df-fv 5135  df-ov 5781  df-oprab 5782  df-mpo 5783  df-pnf 7822  df-mnf 7823  df-xr 7824  df-xadd 9586
This theorem is referenced by:  xaddpnf1  9655  xaddpnf2  9656  xaddmnf1  9657  xaddmnf2  9658  pnfaddmnf  9659  mnfaddpnf  9660  rexadd  9661
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