Metamath Proof Explorer

Theorem iblcncfioo

Description: A continuous function F on an open interval ( A (,) B ) with a finite right limit R in A and a finite left limit L in B is integrable. (Contributed by Glauco Siliprandi, 11-Dec-2019)

Ref Expression
Hypotheses iblcncfioo.a ⊢ ( 𝜑 → 𝐴 ∈ ℝ )
iblcncfioo.b ⊢ ( 𝜑 → 𝐵 ∈ ℝ )
iblcncfioo.f ⊢ ( 𝜑 → 𝐹 ∈ ( ( 𝐴 (,) 𝐵 ) –cn→ ℂ ) )
iblcncfioo.l ⊢ ( 𝜑 → 𝐿 ∈ ( 𝐹 limℂ 𝐵 ) )
iblcncfioo.r ⊢ ( 𝜑 → 𝑅 ∈ ( 𝐹 limℂ 𝐴 ) )
Assertion iblcncfioo ( 𝜑 → 𝐹 ∈ 𝐿1 )

Proof

Step Hyp Ref Expression
1 iblcncfioo.a ⊢ ( 𝜑 → 𝐴 ∈ ℝ )
2 iblcncfioo.b ⊢ ( 𝜑 → 𝐵 ∈ ℝ )
3 iblcncfioo.f ⊢ ( 𝜑 → 𝐹 ∈ ( ( 𝐴 (,) 𝐵 ) –cn→ ℂ ) )
4 iblcncfioo.l ⊢ ( 𝜑 → 𝐿 ∈ ( 𝐹 limℂ 𝐵 ) )
5 iblcncfioo.r ⊢ ( 𝜑 → 𝑅 ∈ ( 𝐹 limℂ 𝐴 ) )
6 cncff ⊢ ( 𝐹 ∈ ( ( 𝐴 (,) 𝐵 ) –cn→ ℂ ) → 𝐹 : ( 𝐴 (,) 𝐵 ) ⟶ ℂ )
7 3 6 syl ⊢ ( 𝜑 → 𝐹 : ( 𝐴 (,) 𝐵 ) ⟶ ℂ )
8 7 feqmptd ⊢ ( 𝜑 → 𝐹 = ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↦ ( 𝐹 ‘ 𝑥 ) ) )
9 1 adantr ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝐴 ∈ ℝ )
10 eliooord ⊢ ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) → ( 𝐴 < 𝑥 ∧ 𝑥 < 𝐵 ) )
11 10 simpld ⊢ ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) → 𝐴 < 𝑥 )
12 11 adantl ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝐴 < 𝑥 )
13 9 12 gtned ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝑥 ≠ 𝐴 )
14 13 neneqd ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → ¬ 𝑥 = 𝐴 )
15 14 iffalsed ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) )
16 elioore ⊢ ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) → 𝑥 ∈ ℝ )
17 16 adantl ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝑥 ∈ ℝ )
18 10 simprd ⊢ ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) → 𝑥 < 𝐵 )
19 18 adantl ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝑥 < 𝐵 )
20 17 19 ltned ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → 𝑥 ≠ 𝐵 )
21 20 neneqd ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → ¬ 𝑥 = 𝐵 )
22 21 iffalsed ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) = ( 𝐹 ‘ 𝑥 ) )
23 15 22 eqtrd ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = ( 𝐹 ‘ 𝑥 ) )
24 23 eqcomd ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → ( 𝐹 ‘ 𝑥 ) = if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) )
25 24 mpteq2dva ⊢ ( 𝜑 → ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↦ ( 𝐹 ‘ 𝑥 ) ) = ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) )
26 8 25 eqtrd ⊢ ( 𝜑 → 𝐹 = ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) )
27 ioossicc ⊢ ( 𝐴 (,) 𝐵 ) ⊆ ( 𝐴 [,] 𝐵 )
28 27 a1i ⊢ ( 𝜑 → ( 𝐴 (,) 𝐵 ) ⊆ ( 𝐴 [,] 𝐵 ) )
29 ioombl ⊢ ( 𝐴 (,) 𝐵 ) ∈ dom vol
30 29 a1i ⊢ ( 𝜑 → ( 𝐴 (,) 𝐵 ) ∈ dom vol )
31 iftrue ⊢ ( 𝑥 = 𝐴 → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = 𝑅 )
32 31 adantl ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = 𝑅 )
33 limccl ⊢ ( 𝐹 limℂ 𝐴 ) ⊆ ℂ
34 33 5 sselid ⊢ ( 𝜑 → 𝑅 ∈ ℂ )
35 34 adantr ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → 𝑅 ∈ ℂ )
36 32 35 eqeltrd ⊢ ( ( 𝜑 ∧ 𝑥 = 𝐴 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
37 36 adantlr ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ 𝑥 = 𝐴 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
38 iffalse ⊢ ( ¬ 𝑥 = 𝐴 → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) )
39 38 ad2antlr ⊢ ( ( ( 𝜑 ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) )
40 iftrue ⊢ ( 𝑥 = 𝐵 → if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) = 𝐿 )
41 40 adantl ⊢ ( ( ( 𝜑 ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) = 𝐿 )
42 39 41 eqtrd ⊢ ( ( ( 𝜑 ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) = 𝐿 )
43 limccl ⊢ ( 𝐹 limℂ 𝐵 ) ⊆ ℂ
44 43 4 sselid ⊢ ( 𝜑 → 𝐿 ∈ ℂ )
45 44 ad2antrr ⊢ ( ( ( 𝜑 ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → 𝐿 ∈ ℂ )
46 42 45 eqeltrd ⊢ ( ( ( 𝜑 ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
47 46 adantllr ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
48 simplll ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝜑 )
49 1 rexrd ⊢ ( 𝜑 → 𝐴 ∈ ℝ* )
50 48 49 syl ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝐴 ∈ ℝ* )
51 2 rexrd ⊢ ( 𝜑 → 𝐵 ∈ ℝ* )
52 48 51 syl ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝐵 ∈ ℝ* )
53 eliccxr ⊢ ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) → 𝑥 ∈ ℝ* )
54 53 ad3antlr ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝑥 ∈ ℝ* )
55 50 52 54 3jca ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → ( 𝐴 ∈ ℝ* ∧ 𝐵 ∈ ℝ* ∧ 𝑥 ∈ ℝ* ) )
56 1 ad2antrr ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → 𝐴 ∈ ℝ )
57 1 adantr ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝐴 ∈ ℝ )
58 2 adantr ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝐵 ∈ ℝ )
59 simpr ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝑥 ∈ ( 𝐴 [,] 𝐵 ) )
60 eliccre ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝑥 ∈ ℝ )
61 57 58 59 60 syl3anc ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝑥 ∈ ℝ )
62 61 adantr ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → 𝑥 ∈ ℝ )
63 1 2 jca ⊢ ( 𝜑 → ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) )
64 63 adantr ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) )
65 elicc2 ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ) → ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↔ ( 𝑥 ∈ ℝ ∧ 𝐴 ≤ 𝑥 ∧ 𝑥 ≤ 𝐵 ) ) )
66 64 65 syl ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↔ ( 𝑥 ∈ ℝ ∧ 𝐴 ≤ 𝑥 ∧ 𝑥 ≤ 𝐵 ) ) )
67 59 66 mpbid ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → ( 𝑥 ∈ ℝ ∧ 𝐴 ≤ 𝑥 ∧ 𝑥 ≤ 𝐵 ) )
68 67 simp2d ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝐴 ≤ 𝑥 )
69 68 adantr ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → 𝐴 ≤ 𝑥 )
70 df-ne ⊢ ( 𝑥 ≠ 𝐴 ↔ ¬ 𝑥 = 𝐴 )
71 70 biimpri ⊢ ( ¬ 𝑥 = 𝐴 → 𝑥 ≠ 𝐴 )
72 71 adantl ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → 𝑥 ≠ 𝐴 )
73 56 62 69 72 leneltd ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → 𝐴 < 𝑥 )
74 73 adantr ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝐴 < 𝑥 )
75 nesym ⊢ ( 𝐵 ≠ 𝑥 ↔ ¬ 𝑥 = 𝐵 )
76 75 biimpri ⊢ ( ¬ 𝑥 = 𝐵 → 𝐵 ≠ 𝑥 )
77 76 adantl ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐵 ) → 𝐵 ≠ 𝑥 )
78 67 simp3d ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → 𝑥 ≤ 𝐵 )
79 61 58 78 3jca ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → ( 𝑥 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝑥 ≤ 𝐵 ) )
80 79 adantr ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐵 ) → ( 𝑥 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝑥 ≤ 𝐵 ) )
81 leltne ⊢ ( ( 𝑥 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ 𝑥 ≤ 𝐵 ) → ( 𝑥 < 𝐵 ↔ 𝐵 ≠ 𝑥 ) )
82 80 81 syl ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐵 ) → ( 𝑥 < 𝐵 ↔ 𝐵 ≠ 𝑥 ) )
83 77 82 mpbird ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐵 ) → 𝑥 < 𝐵 )
84 83 adantlr ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝑥 < 𝐵 )
85 74 84 jca ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → ( 𝐴 < 𝑥 ∧ 𝑥 < 𝐵 ) )
86 elioo3g ⊢ ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↔ ( ( 𝐴 ∈ ℝ* ∧ 𝐵 ∈ ℝ* ∧ 𝑥 ∈ ℝ* ) ∧ ( 𝐴 < 𝑥 ∧ 𝑥 < 𝐵 ) ) )
87 55 85 86 sylanbrc ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → 𝑥 ∈ ( 𝐴 (,) 𝐵 ) )
88 48 87 jca ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) )
89 7 ffvelrnda ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → ( 𝐹 ‘ 𝑥 ) ∈ ℂ )
90 23 89 eqeltrd ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
91 88 90 syl ⊢ ( ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) ∧ ¬ 𝑥 = 𝐵 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
92 47 91 pm2.61dan ⊢ ( ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) ∧ ¬ 𝑥 = 𝐴 ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
93 37 92 pm2.61dan ⊢ ( ( 𝜑 ∧ 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ) → if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ∈ ℂ )
94 nfv ⊢ Ⅎ 𝑥 𝜑
95 eqid ⊢ ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) = ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) )
96 94 95 1 2 3 4 5 cncfiooicc ⊢ ( 𝜑 → ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) ∈ ( ( 𝐴 [,] 𝐵 ) –cn→ ℂ ) )
97 cniccibl ⊢ ( ( 𝐴 ∈ ℝ ∧ 𝐵 ∈ ℝ ∧ ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) ∈ ( ( 𝐴 [,] 𝐵 ) –cn→ ℂ ) ) → ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) ∈ 𝐿1 )
98 1 2 96 97 syl3anc ⊢ ( 𝜑 → ( 𝑥 ∈ ( 𝐴 [,] 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) ∈ 𝐿1 )
99 28 30 93 98 iblss ⊢ ( 𝜑 → ( 𝑥 ∈ ( 𝐴 (,) 𝐵 ) ↦ if ( 𝑥 = 𝐴 , 𝑅 , if ( 𝑥 = 𝐵 , 𝐿 , ( 𝐹 ‘ 𝑥 ) ) ) ) ∈ 𝐿1 )
100 26 99 eqeltrd ⊢ ( 𝜑 → 𝐹 ∈ 𝐿1 )