| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isismty | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 ) )  →  ( 𝐹  ∈  ( 𝑀  Ismty  𝑁 )  ↔  ( 𝐹 : 𝑋 –1-1-onto→ 𝑌  ∧  ∀ 𝑧  ∈  𝑋 ∀ 𝑤  ∈  𝑋 ( 𝑧 𝑀 𝑤 )  =  ( ( 𝐹 ‘ 𝑧 ) 𝑁 ( 𝐹 ‘ 𝑤 ) ) ) ) ) | 
						
							| 2 | 1 | biimp3a | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( 𝐹 : 𝑋 –1-1-onto→ 𝑌  ∧  ∀ 𝑧  ∈  𝑋 ∀ 𝑤  ∈  𝑋 ( 𝑧 𝑀 𝑤 )  =  ( ( 𝐹 ‘ 𝑧 ) 𝑁 ( 𝐹 ‘ 𝑤 ) ) ) ) | 
						
							| 3 | 2 | simpld | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  𝐹 : 𝑋 –1-1-onto→ 𝑌 ) | 
						
							| 4 |  | f1ocnv | ⊢ ( 𝐹 : 𝑋 –1-1-onto→ 𝑌  →  ◡ 𝐹 : 𝑌 –1-1-onto→ 𝑋 ) | 
						
							| 5 |  | f1of | ⊢ ( ◡ 𝐹 : 𝑌 –1-1-onto→ 𝑋  →  ◡ 𝐹 : 𝑌 ⟶ 𝑋 ) | 
						
							| 6 | 3 4 5 | 3syl | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ◡ 𝐹 : 𝑌 ⟶ 𝑋 ) | 
						
							| 7 | 6 | ffvelcdmda | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑦  ∈  𝑌 )  →  ( ◡ 𝐹 ‘ 𝑦 )  ∈  𝑋 ) | 
						
							| 8 |  | oveq1 | ⊢ ( 𝑥  =  ( ◡ 𝐹 ‘ 𝑦 )  →  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) | 
						
							| 9 | 8 | eqeq2d | ⊢ ( 𝑥  =  ( ◡ 𝐹 ‘ 𝑦 )  →  ( 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  ↔  𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 10 | 9 | rexbidv | ⊢ ( 𝑥  =  ( ◡ 𝐹 ‘ 𝑦 )  →  ( ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  ↔  ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 11 | 10 | rspcv | ⊢ ( ( ◡ 𝐹 ‘ 𝑦 )  ∈  𝑋  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 12 | 7 11 | syl | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑦  ∈  𝑌 )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 13 |  | imaeq2 | ⊢ ( 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 )  →  ( 𝐹  “  𝑋 )  =  ( 𝐹  “  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 14 |  | f1ofo | ⊢ ( 𝐹 : 𝑋 –1-1-onto→ 𝑌  →  𝐹 : 𝑋 –onto→ 𝑌 ) | 
						
							| 15 |  | foima | ⊢ ( 𝐹 : 𝑋 –onto→ 𝑌  →  ( 𝐹  “  𝑋 )  =  𝑌 ) | 
						
							| 16 | 3 14 15 | 3syl | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( 𝐹  “  𝑋 )  =  𝑌 ) | 
						
							| 17 | 16 | adantr | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( 𝐹  “  𝑋 )  =  𝑌 ) | 
						
							| 18 |  | rpxr | ⊢ ( 𝑟  ∈  ℝ+  →  𝑟  ∈  ℝ* ) | 
						
							| 19 | 18 | adantl | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑟  ∈  ℝ+ )  →  𝑟  ∈  ℝ* ) | 
						
							| 20 | 7 19 | anim12dan | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( ( ◡ 𝐹 ‘ 𝑦 )  ∈  𝑋  ∧  𝑟  ∈  ℝ* ) ) | 
						
							| 21 |  | ismtyima | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( ( ◡ 𝐹 ‘ 𝑦 )  ∈  𝑋  ∧  𝑟  ∈  ℝ* ) )  →  ( 𝐹  “  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) )  =  ( ( 𝐹 ‘ ( ◡ 𝐹 ‘ 𝑦 ) ) ( ball ‘ 𝑁 ) 𝑟 ) ) | 
						
							| 22 | 20 21 | syldan | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( 𝐹  “  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) )  =  ( ( 𝐹 ‘ ( ◡ 𝐹 ‘ 𝑦 ) ) ( ball ‘ 𝑁 ) 𝑟 ) ) | 
						
							| 23 |  | simpl | ⊢ ( ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ )  →  𝑦  ∈  𝑌 ) | 
						
							| 24 |  | f1ocnvfv2 | ⊢ ( ( 𝐹 : 𝑋 –1-1-onto→ 𝑌  ∧  𝑦  ∈  𝑌 )  →  ( 𝐹 ‘ ( ◡ 𝐹 ‘ 𝑦 ) )  =  𝑦 ) | 
						
							| 25 | 3 23 24 | syl2an | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( 𝐹 ‘ ( ◡ 𝐹 ‘ 𝑦 ) )  =  𝑦 ) | 
						
							| 26 | 25 | oveq1d | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( ( 𝐹 ‘ ( ◡ 𝐹 ‘ 𝑦 ) ) ( ball ‘ 𝑁 ) 𝑟 )  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) | 
						
							| 27 | 22 26 | eqtrd | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( 𝐹  “  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) )  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) | 
						
							| 28 | 17 27 | eqeq12d | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( ( 𝐹  “  𝑋 )  =  ( 𝐹  “  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 ) )  ↔  𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 29 | 13 28 | imbitrid | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  ( 𝑦  ∈  𝑌  ∧  𝑟  ∈  ℝ+ ) )  →  ( 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 )  →  𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 30 | 29 | anassrs | ⊢ ( ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑦  ∈  𝑌 )  ∧  𝑟  ∈  ℝ+ )  →  ( 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 )  →  𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 31 | 30 | reximdva | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑦  ∈  𝑌 )  →  ( ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( ( ◡ 𝐹 ‘ 𝑦 ) ( ball ‘ 𝑀 ) 𝑟 )  →  ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 32 | 12 31 | syld | ⊢ ( ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  ∧  𝑦  ∈  𝑌 )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 33 | 32 | ralrimdva | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 34 |  | simp2 | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  𝑁  ∈  ( ∞Met ‘ 𝑌 ) ) | 
						
							| 35 | 33 34 | jctild | ⊢ ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) ) | 
						
							| 36 | 35 | 3expib | ⊢ ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  →  ( ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) ) ) | 
						
							| 37 | 36 | com12 | ⊢ ( ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  →  ( ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 )  →  ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) ) ) | 
						
							| 38 | 37 | impd | ⊢ ( ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 ) )  →  ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) ) | 
						
							| 39 |  | isbndx | ⊢ ( 𝑀  ∈  ( Bnd ‘ 𝑋 )  ↔  ( 𝑀  ∈  ( ∞Met ‘ 𝑋 )  ∧  ∀ 𝑥  ∈  𝑋 ∃ 𝑟  ∈  ℝ+ 𝑋  =  ( 𝑥 ( ball ‘ 𝑀 ) 𝑟 ) ) ) | 
						
							| 40 |  | isbndx | ⊢ ( 𝑁  ∈  ( Bnd ‘ 𝑌 )  ↔  ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  ∀ 𝑦  ∈  𝑌 ∃ 𝑟  ∈  ℝ+ 𝑌  =  ( 𝑦 ( ball ‘ 𝑁 ) 𝑟 ) ) ) | 
						
							| 41 | 38 39 40 | 3imtr4g | ⊢ ( ( 𝑁  ∈  ( ∞Met ‘ 𝑌 )  ∧  𝐹  ∈  ( 𝑀  Ismty  𝑁 ) )  →  ( 𝑀  ∈  ( Bnd ‘ 𝑋 )  →  𝑁  ∈  ( Bnd ‘ 𝑌 ) ) ) |