| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							uniioombl.1 | 
							⊢ ( 𝜑  →  𝐹 : ℕ ⟶ (  ≤   ∩  ( ℝ  ×  ℝ ) ) )  | 
						
						
							| 2 | 
							
								
							 | 
							uniioombl.2 | 
							⊢ ( 𝜑  →  Disj  𝑥  ∈  ℕ ( (,) ‘ ( 𝐹 ‘ 𝑥 ) ) )  | 
						
						
							| 3 | 
							
								
							 | 
							uniioombl.3 | 
							⊢ 𝑆  =  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝐹 ) )  | 
						
						
							| 4 | 
							
								
							 | 
							uniioombl.a | 
							⊢ 𝐴  =  ∪  ran  ( (,)  ∘  𝐹 )  | 
						
						
							| 5 | 
							
								
							 | 
							uniioombl.e | 
							⊢ ( 𝜑  →  ( vol* ‘ 𝐸 )  ∈  ℝ )  | 
						
						
							| 6 | 
							
								
							 | 
							uniioombl.c | 
							⊢ ( 𝜑  →  𝐶  ∈  ℝ+ )  | 
						
						
							| 7 | 
							
								
							 | 
							uniioombl.g | 
							⊢ ( 𝜑  →  𝐺 : ℕ ⟶ (  ≤   ∩  ( ℝ  ×  ℝ ) ) )  | 
						
						
							| 8 | 
							
								
							 | 
							uniioombl.s | 
							⊢ ( 𝜑  →  𝐸  ⊆  ∪  ran  ( (,)  ∘  𝐺 ) )  | 
						
						
							| 9 | 
							
								
							 | 
							uniioombl.t | 
							⊢ 𝑇  =  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝐺 ) )  | 
						
						
							| 10 | 
							
								
							 | 
							uniioombl.v | 
							⊢ ( 𝜑  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐸 )  +  𝐶 ) )  | 
						
						
							| 11 | 
							
								
							 | 
							eqid | 
							⊢ ( ( abs  ∘   −  )  ∘  𝐺 )  =  ( ( abs  ∘   −  )  ∘  𝐺 )  | 
						
						
							| 12 | 
							
								11 9
							 | 
							ovolsf | 
							⊢ ( 𝐺 : ℕ ⟶ (  ≤   ∩  ( ℝ  ×  ℝ ) )  →  𝑇 : ℕ ⟶ ( 0 [,) +∞ ) )  | 
						
						
							| 13 | 
							
								7 12
							 | 
							syl | 
							⊢ ( 𝜑  →  𝑇 : ℕ ⟶ ( 0 [,) +∞ ) )  | 
						
						
							| 14 | 
							
								13
							 | 
							frnd | 
							⊢ ( 𝜑  →  ran  𝑇  ⊆  ( 0 [,) +∞ ) )  | 
						
						
							| 15 | 
							
								
							 | 
							rge0ssre | 
							⊢ ( 0 [,) +∞ )  ⊆  ℝ  | 
						
						
							| 16 | 
							
								14 15
							 | 
							sstrdi | 
							⊢ ( 𝜑  →  ran  𝑇  ⊆  ℝ )  | 
						
						
							| 17 | 
							
								
							 | 
							1nn | 
							⊢ 1  ∈  ℕ  | 
						
						
							| 18 | 
							
								13
							 | 
							fdmd | 
							⊢ ( 𝜑  →  dom  𝑇  =  ℕ )  | 
						
						
							| 19 | 
							
								17 18
							 | 
							eleqtrrid | 
							⊢ ( 𝜑  →  1  ∈  dom  𝑇 )  | 
						
						
							| 20 | 
							
								19
							 | 
							ne0d | 
							⊢ ( 𝜑  →  dom  𝑇  ≠  ∅ )  | 
						
						
							| 21 | 
							
								
							 | 
							dm0rn0 | 
							⊢ ( dom  𝑇  =  ∅  ↔  ran  𝑇  =  ∅ )  | 
						
						
							| 22 | 
							
								21
							 | 
							necon3bii | 
							⊢ ( dom  𝑇  ≠  ∅  ↔  ran  𝑇  ≠  ∅ )  | 
						
						
							| 23 | 
							
								20 22
							 | 
							sylib | 
							⊢ ( 𝜑  →  ran  𝑇  ≠  ∅ )  | 
						
						
							| 24 | 
							
								
							 | 
							icossxr | 
							⊢ ( 0 [,) +∞ )  ⊆  ℝ*  | 
						
						
							| 25 | 
							
								14 24
							 | 
							sstrdi | 
							⊢ ( 𝜑  →  ran  𝑇  ⊆  ℝ* )  | 
						
						
							| 26 | 
							
								
							 | 
							supxrcl | 
							⊢ ( ran  𝑇  ⊆  ℝ*  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  ∈  ℝ* )  | 
						
						
							| 27 | 
							
								25 26
							 | 
							syl | 
							⊢ ( 𝜑  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  ∈  ℝ* )  | 
						
						
							| 28 | 
							
								6
							 | 
							rpred | 
							⊢ ( 𝜑  →  𝐶  ∈  ℝ )  | 
						
						
							| 29 | 
							
								5 28
							 | 
							readdcld | 
							⊢ ( 𝜑  →  ( ( vol* ‘ 𝐸 )  +  𝐶 )  ∈  ℝ )  | 
						
						
							| 30 | 
							
								29
							 | 
							rexrd | 
							⊢ ( 𝜑  →  ( ( vol* ‘ 𝐸 )  +  𝐶 )  ∈  ℝ* )  | 
						
						
							| 31 | 
							
								
							 | 
							pnfxr | 
							⊢ +∞  ∈  ℝ*  | 
						
						
							| 32 | 
							
								31
							 | 
							a1i | 
							⊢ ( 𝜑  →  +∞  ∈  ℝ* )  | 
						
						
							| 33 | 
							
								29
							 | 
							ltpnfd | 
							⊢ ( 𝜑  →  ( ( vol* ‘ 𝐸 )  +  𝐶 )  <  +∞ )  | 
						
						
							| 34 | 
							
								27 30 32 10 33
							 | 
							xrlelttrd | 
							⊢ ( 𝜑  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  <  +∞ )  | 
						
						
							| 35 | 
							
								
							 | 
							supxrbnd | 
							⊢ ( ( ran  𝑇  ⊆  ℝ  ∧  ran  𝑇  ≠  ∅  ∧  sup ( ran  𝑇 ,  ℝ* ,   <  )  <  +∞ )  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  ∈  ℝ )  | 
						
						
							| 36 | 
							
								16 23 34 35
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  sup ( ran  𝑇 ,  ℝ* ,   <  )  ∈  ℝ )  |