| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ovolsca.1 | ⊢ ( 𝜑  →  𝐴  ⊆  ℝ ) | 
						
							| 2 |  | ovolsca.2 | ⊢ ( 𝜑  →  𝐶  ∈  ℝ+ ) | 
						
							| 3 |  | ovolsca.3 | ⊢ ( 𝜑  →  𝐵  =  { 𝑥  ∈  ℝ  ∣  ( 𝐶  ·  𝑥 )  ∈  𝐴 } ) | 
						
							| 4 |  | ovolsca.4 | ⊢ ( 𝜑  →  ( vol* ‘ 𝐴 )  ∈  ℝ ) | 
						
							| 5 | 1 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  →  𝐴  ⊆  ℝ ) | 
						
							| 6 | 4 | adantr | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  →  ( vol* ‘ 𝐴 )  ∈  ℝ ) | 
						
							| 7 |  | rpmulcl | ⊢ ( ( 𝐶  ∈  ℝ+  ∧  𝑦  ∈  ℝ+ )  →  ( 𝐶  ·  𝑦 )  ∈  ℝ+ ) | 
						
							| 8 | 2 7 | sylan | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  →  ( 𝐶  ·  𝑦 )  ∈  ℝ+ ) | 
						
							| 9 |  | eqid | ⊢ seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) )  =  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) | 
						
							| 10 | 9 | ovolgelb | ⊢ ( ( 𝐴  ⊆  ℝ  ∧  ( vol* ‘ 𝐴 )  ∈  ℝ  ∧  ( 𝐶  ·  𝑦 )  ∈  ℝ+ )  →  ∃ 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ ) ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) | 
						
							| 11 | 5 6 8 10 | syl3anc | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  →  ∃ 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ ) ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) | 
						
							| 12 | 1 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝐴  ⊆  ℝ ) | 
						
							| 13 | 2 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝐶  ∈  ℝ+ ) | 
						
							| 14 | 3 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝐵  =  { 𝑥  ∈  ℝ  ∣  ( 𝐶  ·  𝑥 )  ∈  𝐴 } ) | 
						
							| 15 | 4 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  ( vol* ‘ 𝐴 )  ∈  ℝ ) | 
						
							| 16 |  | 2fveq3 | ⊢ ( 𝑚  =  𝑛  →  ( 1st  ‘ ( 𝑓 ‘ 𝑚 ) )  =  ( 1st  ‘ ( 𝑓 ‘ 𝑛 ) ) ) | 
						
							| 17 | 16 | oveq1d | ⊢ ( 𝑚  =  𝑛  →  ( ( 1st  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 )  =  ( ( 1st  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) ) | 
						
							| 18 |  | 2fveq3 | ⊢ ( 𝑚  =  𝑛  →  ( 2nd  ‘ ( 𝑓 ‘ 𝑚 ) )  =  ( 2nd  ‘ ( 𝑓 ‘ 𝑛 ) ) ) | 
						
							| 19 | 18 | oveq1d | ⊢ ( 𝑚  =  𝑛  →  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 )  =  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) ) | 
						
							| 20 | 17 19 | opeq12d | ⊢ ( 𝑚  =  𝑛  →  〈 ( ( 1st  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 ) ,  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 ) 〉  =  〈 ( ( 1st  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) ,  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) 〉 ) | 
						
							| 21 | 20 | cbvmptv | ⊢ ( 𝑚  ∈  ℕ  ↦  〈 ( ( 1st  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 ) ,  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑚 ) )  /  𝐶 ) 〉 )  =  ( 𝑛  ∈  ℕ  ↦  〈 ( ( 1st  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) ,  ( ( 2nd  ‘ ( 𝑓 ‘ 𝑛 ) )  /  𝐶 ) 〉 ) | 
						
							| 22 |  | elmapi | ⊢ ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  →  𝑓 : ℕ ⟶ (  ≤   ∩  ( ℝ  ×  ℝ ) ) ) | 
						
							| 23 | 22 | ad2antrl | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝑓 : ℕ ⟶ (  ≤   ∩  ( ℝ  ×  ℝ ) ) ) | 
						
							| 24 |  | simprrl | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 ) ) | 
						
							| 25 |  | simplr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  𝑦  ∈  ℝ+ ) | 
						
							| 26 |  | simprrr | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) | 
						
							| 27 | 12 13 14 15 9 21 23 24 25 26 | ovolscalem1 | ⊢ ( ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  ∧  ( 𝑓  ∈  ( (  ≤   ∩  ( ℝ  ×  ℝ ) )  ↑m  ℕ )  ∧  ( 𝐴  ⊆  ∪  ran  ( (,)  ∘  𝑓 )  ∧  sup ( ran  seq 1 (  +  ,  ( ( abs  ∘   −  )  ∘  𝑓 ) ) ,  ℝ* ,   <  )  ≤  ( ( vol* ‘ 𝐴 )  +  ( 𝐶  ·  𝑦 ) ) ) ) )  →  ( vol* ‘ 𝐵 )  ≤  ( ( ( vol* ‘ 𝐴 )  /  𝐶 )  +  𝑦 ) ) | 
						
							| 28 | 11 27 | rexlimddv | ⊢ ( ( 𝜑  ∧  𝑦  ∈  ℝ+ )  →  ( vol* ‘ 𝐵 )  ≤  ( ( ( vol* ‘ 𝐴 )  /  𝐶 )  +  𝑦 ) ) | 
						
							| 29 | 28 | ralrimiva | ⊢ ( 𝜑  →  ∀ 𝑦  ∈  ℝ+ ( vol* ‘ 𝐵 )  ≤  ( ( ( vol* ‘ 𝐴 )  /  𝐶 )  +  𝑦 ) ) | 
						
							| 30 |  | ssrab2 | ⊢ { 𝑥  ∈  ℝ  ∣  ( 𝐶  ·  𝑥 )  ∈  𝐴 }  ⊆  ℝ | 
						
							| 31 | 3 30 | eqsstrdi | ⊢ ( 𝜑  →  𝐵  ⊆  ℝ ) | 
						
							| 32 |  | ovolcl | ⊢ ( 𝐵  ⊆  ℝ  →  ( vol* ‘ 𝐵 )  ∈  ℝ* ) | 
						
							| 33 | 31 32 | syl | ⊢ ( 𝜑  →  ( vol* ‘ 𝐵 )  ∈  ℝ* ) | 
						
							| 34 | 4 2 | rerpdivcld | ⊢ ( 𝜑  →  ( ( vol* ‘ 𝐴 )  /  𝐶 )  ∈  ℝ ) | 
						
							| 35 |  | xralrple | ⊢ ( ( ( vol* ‘ 𝐵 )  ∈  ℝ*  ∧  ( ( vol* ‘ 𝐴 )  /  𝐶 )  ∈  ℝ )  →  ( ( vol* ‘ 𝐵 )  ≤  ( ( vol* ‘ 𝐴 )  /  𝐶 )  ↔  ∀ 𝑦  ∈  ℝ+ ( vol* ‘ 𝐵 )  ≤  ( ( ( vol* ‘ 𝐴 )  /  𝐶 )  +  𝑦 ) ) ) | 
						
							| 36 | 33 34 35 | syl2anc | ⊢ ( 𝜑  →  ( ( vol* ‘ 𝐵 )  ≤  ( ( vol* ‘ 𝐴 )  /  𝐶 )  ↔  ∀ 𝑦  ∈  ℝ+ ( vol* ‘ 𝐵 )  ≤  ( ( ( vol* ‘ 𝐴 )  /  𝐶 )  +  𝑦 ) ) ) | 
						
							| 37 | 29 36 | mpbird | ⊢ ( 𝜑  →  ( vol* ‘ 𝐵 )  ≤  ( ( vol* ‘ 𝐴 )  /  𝐶 ) ) |