| Step | Hyp | Ref | Expression | 
						
							| 1 |  | i1fadd.1 | ⊢ ( 𝜑  →  𝐹  ∈  dom  ∫1 ) | 
						
							| 2 |  | i1fadd.2 | ⊢ ( 𝜑  →  𝐺  ∈  dom  ∫1 ) | 
						
							| 3 |  | itg1add.3 | ⊢ 𝐼  =  ( 𝑖  ∈  ℝ ,  𝑗  ∈  ℝ  ↦  if ( ( 𝑖  =  0  ∧  𝑗  =  0 ) ,  0 ,  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑖 } )  ∩  ( ◡ 𝐺  “  { 𝑗 } ) ) ) ) ) | 
						
							| 4 |  | itg1add.4 | ⊢ 𝑃  =  (  +   ↾  ( ran  𝐹  ×  ran  𝐺 ) ) | 
						
							| 5 |  | i1frn | ⊢ ( 𝐹  ∈  dom  ∫1  →  ran  𝐹  ∈  Fin ) | 
						
							| 6 | 1 5 | syl | ⊢ ( 𝜑  →  ran  𝐹  ∈  Fin ) | 
						
							| 7 |  | i1frn | ⊢ ( 𝐺  ∈  dom  ∫1  →  ran  𝐺  ∈  Fin ) | 
						
							| 8 | 2 7 | syl | ⊢ ( 𝜑  →  ran  𝐺  ∈  Fin ) | 
						
							| 9 | 8 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  ran  𝐺  ∈  Fin ) | 
						
							| 10 |  | i1ff | ⊢ ( 𝐹  ∈  dom  ∫1  →  𝐹 : ℝ ⟶ ℝ ) | 
						
							| 11 | 1 10 | syl | ⊢ ( 𝜑  →  𝐹 : ℝ ⟶ ℝ ) | 
						
							| 12 | 11 | frnd | ⊢ ( 𝜑  →  ran  𝐹  ⊆  ℝ ) | 
						
							| 13 | 12 | sselda | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  𝑦  ∈  ℝ ) | 
						
							| 14 | 13 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ∈  ℝ ) | 
						
							| 15 | 14 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ∈  ℂ ) | 
						
							| 16 | 1 2 3 | itg1addlem2 | ⊢ ( 𝜑  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 17 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 18 |  | i1ff | ⊢ ( 𝐺  ∈  dom  ∫1  →  𝐺 : ℝ ⟶ ℝ ) | 
						
							| 19 | 2 18 | syl | ⊢ ( 𝜑  →  𝐺 : ℝ ⟶ ℝ ) | 
						
							| 20 | 19 | frnd | ⊢ ( 𝜑  →  ran  𝐺  ⊆  ℝ ) | 
						
							| 21 | 20 | sselda | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  →  𝑧  ∈  ℝ ) | 
						
							| 22 | 21 | adantlr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑧  ∈  ℝ ) | 
						
							| 23 | 17 14 22 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 24 | 23 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 25 | 15 24 | mulcld | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 26 | 9 25 | fsumcl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 27 | 22 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑧  ∈  ℂ ) | 
						
							| 28 | 27 24 | mulcld | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 29 | 9 28 | fsumcl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 30 | 6 26 29 | fsumadd | ⊢ ( 𝜑  →  Σ 𝑦  ∈  ran  𝐹 ( Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) )  =  ( Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 31 | 1 2 3 4 | itg1addlem4 | ⊢ ( 𝜑  →  ( ∫1 ‘ ( 𝐹  ∘f   +  𝐺 ) )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  +  𝑧 )  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 32 | 15 27 24 | adddird | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  ∧  𝑧  ∈  ran  𝐺 )  →  ( ( 𝑦  +  𝑧 )  ·  ( 𝑦 𝐼 𝑧 ) )  =  ( ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 33 | 32 | sumeq2dv | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  +  𝑧 )  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 34 | 9 25 28 | fsumadd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) )  =  ( Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 35 | 33 34 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ran  𝐹 )  →  Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  +  𝑧 )  ·  ( 𝑦 𝐼 𝑧 ) )  =  ( Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 36 | 35 | sumeq2dv | ⊢ ( 𝜑  →  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( ( 𝑦  +  𝑧 )  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 ( Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 37 | 31 36 | eqtrd | ⊢ ( 𝜑  →  ( ∫1 ‘ ( 𝐹  ∘f   +  𝐺 ) )  =  Σ 𝑦  ∈  ran  𝐹 ( Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 38 |  | itg1val | ⊢ ( 𝐹  ∈  dom  ∫1  →  ( ∫1 ‘ 𝐹 )  =  Σ 𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) ( 𝑦  ·  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) ) ) ) | 
						
							| 39 | 1 38 | syl | ⊢ ( 𝜑  →  ( ∫1 ‘ 𝐹 )  =  Σ 𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) ( 𝑦  ·  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) ) ) ) | 
						
							| 40 | 19 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  𝐺 : ℝ ⟶ ℝ ) | 
						
							| 41 | 8 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ran  𝐺  ∈  Fin ) | 
						
							| 42 |  | inss2 | ⊢ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ⊆  ( ◡ 𝐺  “  { 𝑧 } ) | 
						
							| 43 | 42 | a1i | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ⊆  ( ◡ 𝐺  “  { 𝑧 } ) ) | 
						
							| 44 |  | i1fima | ⊢ ( 𝐹  ∈  dom  ∫1  →  ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol ) | 
						
							| 45 | 1 44 | syl | ⊢ ( 𝜑  →  ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol ) | 
						
							| 46 | 45 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol ) | 
						
							| 47 |  | i1fima | ⊢ ( 𝐺  ∈  dom  ∫1  →  ( ◡ 𝐺  “  { 𝑧 } )  ∈  dom  vol ) | 
						
							| 48 | 2 47 | syl | ⊢ ( 𝜑  →  ( ◡ 𝐺  “  { 𝑧 } )  ∈  dom  vol ) | 
						
							| 49 | 48 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( ◡ 𝐺  “  { 𝑧 } )  ∈  dom  vol ) | 
						
							| 50 |  | inmbl | ⊢ ( ( ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol  ∧  ( ◡ 𝐺  “  { 𝑧 } )  ∈  dom  vol )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ∈  dom  vol ) | 
						
							| 51 | 46 49 50 | syl2anc | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ∈  dom  vol ) | 
						
							| 52 | 12 | ssdifssd | ⊢ ( 𝜑  →  ( ran  𝐹  ∖  { 0 } )  ⊆  ℝ ) | 
						
							| 53 | 52 | sselda | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  𝑦  ∈  ℝ ) | 
						
							| 54 | 53 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ∈  ℝ ) | 
						
							| 55 | 20 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ran  𝐺  ⊆  ℝ ) | 
						
							| 56 | 55 | sselda | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑧  ∈  ℝ ) | 
						
							| 57 |  | eldifsni | ⊢ ( 𝑦  ∈  ( ran  𝐹  ∖  { 0 } )  →  𝑦  ≠  0 ) | 
						
							| 58 | 57 | ad2antlr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ≠  0 ) | 
						
							| 59 |  | simpl | ⊢ ( ( 𝑦  =  0  ∧  𝑧  =  0 )  →  𝑦  =  0 ) | 
						
							| 60 | 59 | necon3ai | ⊢ ( 𝑦  ≠  0  →  ¬  ( 𝑦  =  0  ∧  𝑧  =  0 ) ) | 
						
							| 61 | 58 60 | syl | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ¬  ( 𝑦  =  0  ∧  𝑧  =  0 ) ) | 
						
							| 62 | 1 2 3 | itg1addlem3 | ⊢ ( ( ( 𝑦  ∈  ℝ  ∧  𝑧  ∈  ℝ )  ∧  ¬  ( 𝑦  =  0  ∧  𝑧  =  0 ) )  →  ( 𝑦 𝐼 𝑧 )  =  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 63 | 54 56 61 62 | syl21anc | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  =  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 64 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 65 | 64 54 56 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 66 | 63 65 | eqeltrrd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) )  ∈  ℝ ) | 
						
							| 67 | 40 41 43 51 66 | itg1addlem1 | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( vol ‘ ∪  𝑧  ∈  ran  𝐺 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) )  =  Σ 𝑧  ∈  ran  𝐺 ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 68 |  | iunin2 | ⊢ ∪  𝑧  ∈  ran  𝐺 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } ) ) | 
						
							| 69 | 1 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  𝐹  ∈  dom  ∫1 ) | 
						
							| 70 | 69 44 | syl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol ) | 
						
							| 71 |  | mblss | ⊢ ( ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol  →  ( ◡ 𝐹  “  { 𝑦 } )  ⊆  ℝ ) | 
						
							| 72 | 70 71 | syl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( ◡ 𝐹  “  { 𝑦 } )  ⊆  ℝ ) | 
						
							| 73 |  | iunid | ⊢ ∪  𝑧  ∈  ran  𝐺 { 𝑧 }  =  ran  𝐺 | 
						
							| 74 | 73 | imaeq2i | ⊢ ( ◡ 𝐺  “  ∪  𝑧  ∈  ran  𝐺 { 𝑧 } )  =  ( ◡ 𝐺  “  ran  𝐺 ) | 
						
							| 75 |  | imaiun | ⊢ ( ◡ 𝐺  “  ∪  𝑧  ∈  ran  𝐺 { 𝑧 } )  =  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } ) | 
						
							| 76 |  | cnvimarndm | ⊢ ( ◡ 𝐺  “  ran  𝐺 )  =  dom  𝐺 | 
						
							| 77 | 74 75 76 | 3eqtr3i | ⊢ ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } )  =  dom  𝐺 | 
						
							| 78 | 40 | fdmd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  dom  𝐺  =  ℝ ) | 
						
							| 79 | 77 78 | eqtrid | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } )  =  ℝ ) | 
						
							| 80 | 72 79 | sseqtrrd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( ◡ 𝐹  “  { 𝑦 } )  ⊆  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } ) ) | 
						
							| 81 |  | dfss2 | ⊢ ( ( ◡ 𝐹  “  { 𝑦 } )  ⊆  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } )  ↔  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 82 | 80 81 | sylib | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ∪  𝑧  ∈  ran  𝐺 ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 83 | 68 82 | eqtr2id | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( ◡ 𝐹  “  { 𝑦 } )  =  ∪  𝑧  ∈  ran  𝐺 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) | 
						
							| 84 | 83 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) )  =  ( vol ‘ ∪  𝑧  ∈  ran  𝐺 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 85 | 63 | sumeq2dv | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦 𝐼 𝑧 )  =  Σ 𝑧  ∈  ran  𝐺 ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 86 | 67 84 85 | 3eqtr4d | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) )  =  Σ 𝑧  ∈  ran  𝐺 ( 𝑦 𝐼 𝑧 ) ) | 
						
							| 87 | 86 | oveq2d | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( 𝑦  ·  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) ) )  =  ( 𝑦  ·  Σ 𝑧  ∈  ran  𝐺 ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 88 | 53 | recnd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  𝑦  ∈  ℂ ) | 
						
							| 89 | 65 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 90 | 41 88 89 | fsummulc2 | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( 𝑦  ·  Σ 𝑧  ∈  ran  𝐺 ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 91 | 87 90 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  ( 𝑦  ·  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) ) )  =  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 92 | 91 | sumeq2dv | ⊢ ( 𝜑  →  Σ 𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) ( 𝑦  ·  ( vol ‘ ( ◡ 𝐹  “  { 𝑦 } ) ) )  =  Σ 𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 93 |  | difssd | ⊢ ( 𝜑  →  ( ran  𝐹  ∖  { 0 } )  ⊆  ran  𝐹 ) | 
						
							| 94 | 54 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ∈  ℂ ) | 
						
							| 95 | 94 89 | mulcld | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 96 | 41 95 | fsumcl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 97 |  | dfin4 | ⊢ ( ran  𝐹  ∩  { 0 } )  =  ( ran  𝐹  ∖  ( ran  𝐹  ∖  { 0 } ) ) | 
						
							| 98 |  | inss2 | ⊢ ( ran  𝐹  ∩  { 0 } )  ⊆  { 0 } | 
						
							| 99 | 97 98 | eqsstrri | ⊢ ( ran  𝐹  ∖  ( ran  𝐹  ∖  { 0 } ) )  ⊆  { 0 } | 
						
							| 100 | 99 | sseli | ⊢ ( 𝑦  ∈  ( ran  𝐹  ∖  ( ran  𝐹  ∖  { 0 } ) )  →  𝑦  ∈  { 0 } ) | 
						
							| 101 |  | elsni | ⊢ ( 𝑦  ∈  { 0 }  →  𝑦  =  0 ) | 
						
							| 102 | 101 | ad2antlr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  =  0 ) | 
						
							| 103 | 102 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  ( 0  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 104 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 105 |  | 0re | ⊢ 0  ∈  ℝ | 
						
							| 106 | 102 105 | eqeltrdi | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑦  ∈  ℝ ) | 
						
							| 107 | 21 | adantlr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  𝑧  ∈  ℝ ) | 
						
							| 108 | 104 106 107 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 109 | 108 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 110 | 109 | mul02d | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 0  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 111 | 103 110 | eqtrd | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  ∧  𝑧  ∈  ran  𝐺 )  →  ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 112 | 111 | sumeq2dv | ⊢ ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑧  ∈  ran  𝐺 0 ) | 
						
							| 113 | 8 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  →  ran  𝐺  ∈  Fin ) | 
						
							| 114 | 113 | olcd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  →  ( ran  𝐺  ⊆  ( ℤ≥ ‘ 0 )  ∨  ran  𝐺  ∈  Fin ) ) | 
						
							| 115 |  | sumz | ⊢ ( ( ran  𝐺  ⊆  ( ℤ≥ ‘ 0 )  ∨  ran  𝐺  ∈  Fin )  →  Σ 𝑧  ∈  ran  𝐺 0  =  0 ) | 
						
							| 116 | 114 115 | syl | ⊢ ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  →  Σ 𝑧  ∈  ran  𝐺 0  =  0 ) | 
						
							| 117 | 112 116 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑦  ∈  { 0 } )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 118 | 100 117 | sylan2 | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ( ran  𝐹  ∖  ( ran  𝐹  ∖  { 0 } ) ) )  →  Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 119 | 93 96 118 6 | fsumss | ⊢ ( 𝜑  →  Σ 𝑦  ∈  ( ran  𝐹  ∖  { 0 } ) Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 120 | 39 92 119 | 3eqtrd | ⊢ ( 𝜑  →  ( ∫1 ‘ 𝐹 )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 121 |  | itg1val | ⊢ ( 𝐺  ∈  dom  ∫1  →  ( ∫1 ‘ 𝐺 )  =  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) ( 𝑧  ·  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 122 | 2 121 | syl | ⊢ ( 𝜑  →  ( ∫1 ‘ 𝐺 )  =  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) ( 𝑧  ·  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 123 | 11 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  𝐹 : ℝ ⟶ ℝ ) | 
						
							| 124 | 6 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ran  𝐹  ∈  Fin ) | 
						
							| 125 |  | inss1 | ⊢ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ⊆  ( ◡ 𝐹  “  { 𝑦 } ) | 
						
							| 126 | 125 | a1i | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ⊆  ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 127 | 45 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( ◡ 𝐹  “  { 𝑦 } )  ∈  dom  vol ) | 
						
							| 128 | 48 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( ◡ 𝐺  “  { 𝑧 } )  ∈  dom  vol ) | 
						
							| 129 | 127 128 50 | syl2anc | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  ∈  dom  vol ) | 
						
							| 130 | 12 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ran  𝐹  ⊆  ℝ ) | 
						
							| 131 | 130 | sselda | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑦  ∈  ℝ ) | 
						
							| 132 | 20 | ssdifssd | ⊢ ( 𝜑  →  ( ran  𝐺  ∖  { 0 } )  ⊆  ℝ ) | 
						
							| 133 | 132 | sselda | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  𝑧  ∈  ℝ ) | 
						
							| 134 | 133 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ∈  ℝ ) | 
						
							| 135 |  | eldifsni | ⊢ ( 𝑧  ∈  ( ran  𝐺  ∖  { 0 } )  →  𝑧  ≠  0 ) | 
						
							| 136 | 135 | ad2antlr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ≠  0 ) | 
						
							| 137 |  | simpr | ⊢ ( ( 𝑦  =  0  ∧  𝑧  =  0 )  →  𝑧  =  0 ) | 
						
							| 138 | 137 | necon3ai | ⊢ ( 𝑧  ≠  0  →  ¬  ( 𝑦  =  0  ∧  𝑧  =  0 ) ) | 
						
							| 139 | 136 138 | syl | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ¬  ( 𝑦  =  0  ∧  𝑧  =  0 ) ) | 
						
							| 140 | 131 134 139 62 | syl21anc | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  =  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 141 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 142 | 141 131 134 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 143 | 140 142 | eqeltrrd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) )  ∈  ℝ ) | 
						
							| 144 | 123 124 126 129 143 | itg1addlem1 | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( vol ‘ ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) )  =  Σ 𝑦  ∈  ran  𝐹 ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 145 |  | incom | ⊢ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 146 | 145 | a1i | ⊢ ( 𝑦  ∈  ran  𝐹  →  ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ( ◡ 𝐹  “  { 𝑦 } ) ) ) | 
						
							| 147 | 146 | iuneq2i | ⊢ ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  =  ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 148 |  | iunin2 | ⊢ ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ( ◡ 𝐹  “  { 𝑦 } ) )  =  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 149 | 147 148 | eqtri | ⊢ ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 150 |  | cnvimass | ⊢ ( ◡ 𝐺  “  { 𝑧 } )  ⊆  dom  𝐺 | 
						
							| 151 | 19 | fdmd | ⊢ ( 𝜑  →  dom  𝐺  =  ℝ ) | 
						
							| 152 | 151 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  dom  𝐺  =  ℝ ) | 
						
							| 153 | 150 152 | sseqtrid | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( ◡ 𝐺  “  { 𝑧 } )  ⊆  ℝ ) | 
						
							| 154 |  | iunid | ⊢ ∪  𝑦  ∈  ran  𝐹 { 𝑦 }  =  ran  𝐹 | 
						
							| 155 | 154 | imaeq2i | ⊢ ( ◡ 𝐹  “  ∪  𝑦  ∈  ran  𝐹 { 𝑦 } )  =  ( ◡ 𝐹  “  ran  𝐹 ) | 
						
							| 156 |  | imaiun | ⊢ ( ◡ 𝐹  “  ∪  𝑦  ∈  ran  𝐹 { 𝑦 } )  =  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) | 
						
							| 157 |  | cnvimarndm | ⊢ ( ◡ 𝐹  “  ran  𝐹 )  =  dom  𝐹 | 
						
							| 158 | 155 156 157 | 3eqtr3i | ⊢ ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } )  =  dom  𝐹 | 
						
							| 159 | 11 | fdmd | ⊢ ( 𝜑  →  dom  𝐹  =  ℝ ) | 
						
							| 160 | 159 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  dom  𝐹  =  ℝ ) | 
						
							| 161 | 158 160 | eqtrid | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } )  =  ℝ ) | 
						
							| 162 | 153 161 | sseqtrrd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( ◡ 𝐺  “  { 𝑧 } )  ⊆  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) ) | 
						
							| 163 |  | dfss2 | ⊢ ( ( ◡ 𝐺  “  { 𝑧 } )  ⊆  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } )  ↔  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) )  =  ( ◡ 𝐺  “  { 𝑧 } ) ) | 
						
							| 164 | 162 163 | sylib | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( ( ◡ 𝐺  “  { 𝑧 } )  ∩  ∪  𝑦  ∈  ran  𝐹 ( ◡ 𝐹  “  { 𝑦 } ) )  =  ( ◡ 𝐺  “  { 𝑧 } ) ) | 
						
							| 165 | 149 164 | eqtr2id | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( ◡ 𝐺  “  { 𝑧 } )  =  ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) | 
						
							| 166 | 165 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) )  =  ( vol ‘ ∪  𝑦  ∈  ran  𝐹 ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 167 | 140 | sumeq2dv | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  Σ 𝑦  ∈  ran  𝐹 ( 𝑦 𝐼 𝑧 )  =  Σ 𝑦  ∈  ran  𝐹 ( vol ‘ ( ( ◡ 𝐹  “  { 𝑦 } )  ∩  ( ◡ 𝐺  “  { 𝑧 } ) ) ) ) | 
						
							| 168 | 144 166 167 | 3eqtr4d | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) )  =  Σ 𝑦  ∈  ran  𝐹 ( 𝑦 𝐼 𝑧 ) ) | 
						
							| 169 | 168 | oveq2d | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( 𝑧  ·  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) ) )  =  ( 𝑧  ·  Σ 𝑦  ∈  ran  𝐹 ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 170 | 133 | recnd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  𝑧  ∈  ℂ ) | 
						
							| 171 | 142 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 172 | 124 170 171 | fsummulc2 | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( 𝑧  ·  Σ 𝑦  ∈  ran  𝐹 ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 173 | 169 172 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  ( 𝑧  ·  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) ) )  =  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 174 | 173 | sumeq2dv | ⊢ ( 𝜑  →  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) ( 𝑧  ·  ( vol ‘ ( ◡ 𝐺  “  { 𝑧 } ) ) )  =  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 175 |  | difssd | ⊢ ( 𝜑  →  ( ran  𝐺  ∖  { 0 } )  ⊆  ran  𝐺 ) | 
						
							| 176 | 170 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ∈  ℂ ) | 
						
							| 177 | 176 171 | mulcld | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 178 | 124 177 | fsumcl | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) )  →  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 179 |  | dfin4 | ⊢ ( ran  𝐺  ∩  { 0 } )  =  ( ran  𝐺  ∖  ( ran  𝐺  ∖  { 0 } ) ) | 
						
							| 180 |  | inss2 | ⊢ ( ran  𝐺  ∩  { 0 } )  ⊆  { 0 } | 
						
							| 181 | 179 180 | eqsstrri | ⊢ ( ran  𝐺  ∖  ( ran  𝐺  ∖  { 0 } ) )  ⊆  { 0 } | 
						
							| 182 | 181 | sseli | ⊢ ( 𝑧  ∈  ( ran  𝐺  ∖  ( ran  𝐺  ∖  { 0 } ) )  →  𝑧  ∈  { 0 } ) | 
						
							| 183 |  | elsni | ⊢ ( 𝑧  ∈  { 0 }  →  𝑧  =  0 ) | 
						
							| 184 | 183 | ad2antlr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  =  0 ) | 
						
							| 185 | 184 | oveq1d | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  ( 0  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 186 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 187 | 13 | adantlr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑦  ∈  ℝ ) | 
						
							| 188 | 184 105 | eqeltrdi | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ∈  ℝ ) | 
						
							| 189 | 186 187 188 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 190 | 189 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 191 | 190 | mul02d | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 0  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 192 | 185 191 | eqtrd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 193 | 192 | sumeq2dv | ⊢ ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  →  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 0 ) | 
						
							| 194 | 6 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  →  ran  𝐹  ∈  Fin ) | 
						
							| 195 | 194 | olcd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  →  ( ran  𝐹  ⊆  ( ℤ≥ ‘ 0 )  ∨  ran  𝐹  ∈  Fin ) ) | 
						
							| 196 |  | sumz | ⊢ ( ( ran  𝐹  ⊆  ( ℤ≥ ‘ 0 )  ∨  ran  𝐹  ∈  Fin )  →  Σ 𝑦  ∈  ran  𝐹 0  =  0 ) | 
						
							| 197 | 195 196 | syl | ⊢ ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  →  Σ 𝑦  ∈  ran  𝐹 0  =  0 ) | 
						
							| 198 | 193 197 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑧  ∈  { 0 } )  →  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 199 | 182 198 | sylan2 | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ( ran  𝐺  ∖  ( ran  𝐺  ∖  { 0 } ) ) )  →  Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  0 ) | 
						
							| 200 | 175 178 199 8 | fsumss | ⊢ ( 𝜑  →  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑧  ∈  ran  𝐺 Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 201 | 21 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ∈  ℝ ) | 
						
							| 202 | 201 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑧  ∈  ℂ ) | 
						
							| 203 | 16 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  𝐼 : ( ℝ  ×  ℝ ) ⟶ ℝ ) | 
						
							| 204 | 12 | adantr | ⊢ ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  →  ran  𝐹  ⊆  ℝ ) | 
						
							| 205 | 204 | sselda | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  𝑦  ∈  ℝ ) | 
						
							| 206 | 203 205 201 | fovcdmd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℝ ) | 
						
							| 207 | 206 | recnd | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑦 𝐼 𝑧 )  ∈  ℂ ) | 
						
							| 208 | 202 207 | mulcld | ⊢ ( ( ( 𝜑  ∧  𝑧  ∈  ran  𝐺 )  ∧  𝑦  ∈  ran  𝐹 )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 209 | 208 | anasss | ⊢ ( ( 𝜑  ∧  ( 𝑧  ∈  ran  𝐺  ∧  𝑦  ∈  ran  𝐹 ) )  →  ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  ∈  ℂ ) | 
						
							| 210 | 8 6 209 | fsumcom | ⊢ ( 𝜑  →  Σ 𝑧  ∈  ran  𝐺 Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 211 | 200 210 | eqtrd | ⊢ ( 𝜑  →  Σ 𝑧  ∈  ( ran  𝐺  ∖  { 0 } ) Σ 𝑦  ∈  ran  𝐹 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 212 | 122 174 211 | 3eqtrd | ⊢ ( 𝜑  →  ( ∫1 ‘ 𝐺 )  =  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) | 
						
							| 213 | 120 212 | oveq12d | ⊢ ( 𝜑  →  ( ( ∫1 ‘ 𝐹 )  +  ( ∫1 ‘ 𝐺 ) )  =  ( Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑦  ·  ( 𝑦 𝐼 𝑧 ) )  +  Σ 𝑦  ∈  ran  𝐹 Σ 𝑧  ∈  ran  𝐺 ( 𝑧  ·  ( 𝑦 𝐼 𝑧 ) ) ) ) | 
						
							| 214 | 30 37 213 | 3eqtr4d | ⊢ ( 𝜑  →  ( ∫1 ‘ ( 𝐹  ∘f   +  𝐺 ) )  =  ( ( ∫1 ‘ 𝐹 )  +  ( ∫1 ‘ 𝐺 ) ) ) |