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 Description: Lemma for itg1add 23274. (Contributed by Mario Carneiro, 26-Jun-2014.)
Hypotheses
Ref Expression
i1fadd.1 (𝜑𝐹 ∈ dom ∫1)
i1fadd.2 (𝜑𝐺 ∈ dom ∫1)
itg1add.3 𝐼 = (𝑖 ∈ ℝ, 𝑗 ∈ ℝ ↦ if((𝑖 = 0 ∧ 𝑗 = 0), 0, (vol‘((𝐹 “ {𝑖}) ∩ (𝐺 “ {𝑗})))))
Assertion
Ref Expression
itg1addlem3 (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) ∧ ¬ (𝐴 = 0 ∧ 𝐵 = 0)) → (𝐴𝐼𝐵) = (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵}))))
Distinct variable groups:   𝑖,𝑗,𝐴   𝐵,𝑖,𝑗   𝑖,𝐹,𝑗   𝑖,𝐺,𝑗   𝜑,𝑖,𝑗
Allowed substitution hints:   𝐼(𝑖,𝑗)

Proof of Theorem itg1addlem3
StepHypRef Expression
1 eqeq1 2614 . . . . 5 (𝑖 = 𝐴 → (𝑖 = 0 ↔ 𝐴 = 0))
2 eqeq1 2614 . . . . 5 (𝑗 = 𝐵 → (𝑗 = 0 ↔ 𝐵 = 0))
31, 2bi2anan9 913 . . . 4 ((𝑖 = 𝐴𝑗 = 𝐵) → ((𝑖 = 0 ∧ 𝑗 = 0) ↔ (𝐴 = 0 ∧ 𝐵 = 0)))
4 sneq 4135 . . . . . . 7 (𝑖 = 𝐴 → {𝑖} = {𝐴})
54imaeq2d 5385 . . . . . 6 (𝑖 = 𝐴 → (𝐹 “ {𝑖}) = (𝐹 “ {𝐴}))
6 sneq 4135 . . . . . . 7 (𝑗 = 𝐵 → {𝑗} = {𝐵})
76imaeq2d 5385 . . . . . 6 (𝑗 = 𝐵 → (𝐺 “ {𝑗}) = (𝐺 “ {𝐵}))
85, 7ineqan12d 3778 . . . . 5 ((𝑖 = 𝐴𝑗 = 𝐵) → ((𝐹 “ {𝑖}) ∩ (𝐺 “ {𝑗})) = ((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵})))
98fveq2d 6107 . . . 4 ((𝑖 = 𝐴𝑗 = 𝐵) → (vol‘((𝐹 “ {𝑖}) ∩ (𝐺 “ {𝑗}))) = (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵}))))
103, 9ifbieq2d 4061 . . 3 ((𝑖 = 𝐴𝑗 = 𝐵) → if((𝑖 = 0 ∧ 𝑗 = 0), 0, (vol‘((𝐹 “ {𝑖}) ∩ (𝐺 “ {𝑗})))) = if((𝐴 = 0 ∧ 𝐵 = 0), 0, (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵})))))
11 itg1add.3 . . 3 𝐼 = (𝑖 ∈ ℝ, 𝑗 ∈ ℝ ↦ if((𝑖 = 0 ∧ 𝑗 = 0), 0, (vol‘((𝐹 “ {𝑖}) ∩ (𝐺 “ {𝑗})))))
12 c0ex 9913 . . . 4 0 ∈ V
13 fvex 6113 . . . 4 (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵}))) ∈ V
1412, 13ifex 4106 . . 3 if((𝐴 = 0 ∧ 𝐵 = 0), 0, (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵})))) ∈ V
1510, 11, 14ovmpt2a 6689 . 2 ((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) → (𝐴𝐼𝐵) = if((𝐴 = 0 ∧ 𝐵 = 0), 0, (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵})))))
16 iffalse 4045 . 2 (¬ (𝐴 = 0 ∧ 𝐵 = 0) → if((𝐴 = 0 ∧ 𝐵 = 0), 0, (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵})))) = (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵}))))
1715, 16sylan9eq 2664 1 (((𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ) ∧ ¬ (𝐴 = 0 ∧ 𝐵 = 0)) → (𝐴𝐼𝐵) = (vol‘((𝐹 “ {𝐴}) ∩ (𝐺 “ {𝐵}))))
 Colors of variables: wff setvar class Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 383   = wceq 1475   ∈ wcel 1977   ∩ cin 3539  ifcif 4036  {csn 4125  ◡ccnv 5037  dom cdm 5038   “ cima 5041  ‘cfv 5804  (class class class)co 6549   ↦ cmpt2 6551  ℝcr 9814  0cc0 9815  volcvol 23039  ∫1citg1 23190 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-9 1986  ax-10 2006  ax-11 2021  ax-12 2034  ax-13 2234  ax-ext 2590  ax-sep 4709  ax-nul 4717  ax-pr 4833  ax-1cn 9873  ax-icn 9874  ax-addcl 9875  ax-mulcl 9877  ax-i2m1 9883 This theorem depends on definitions:  df-bi 196  df-or 384  df-an 385  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-ral 2901  df-rex 2902  df-rab 2905  df-v 3175  df-sbc 3403  df-dif 3543  df-un 3545  df-in 3547  df-ss 3554  df-nul 3875  df-if 4037  df-sn 4126  df-pr 4128  df-op 4132  df-uni 4373  df-br 4584  df-opab 4644  df-id 4953  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-iota 5768  df-fun 5806  df-fv 5812  df-ov 6552  df-oprab 6553  df-mpt2 6554 This theorem is referenced by:  itg1addlem4  23272  itg1addlem5  23273
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