| Step | Hyp | Ref | Expression | 
						
							| 1 |  | metust.1 | ⊢ 𝐹  =  ran  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 2 |  | simpll | ⊢ ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  𝑎  ∈  ℝ+ ) | 
						
							| 3 | 2 | rpred | ⊢ ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  𝑎  ∈  ℝ ) | 
						
							| 4 |  | simplr | ⊢ ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  𝑏  ∈  ℝ+ ) | 
						
							| 5 | 4 | rpred | ⊢ ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  𝑏  ∈  ℝ ) | 
						
							| 6 |  | simpllr | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  𝑏  ∈  ℝ+ ) | 
						
							| 7 | 6 | rpred | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  𝑏  ∈  ℝ ) | 
						
							| 8 |  | 0xr | ⊢ 0  ∈  ℝ* | 
						
							| 9 | 8 | a1i | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  0  ∈  ℝ* ) | 
						
							| 10 |  | simpl | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  𝑏  ∈  ℝ ) | 
						
							| 11 | 10 | rexrd | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  𝑏  ∈  ℝ* ) | 
						
							| 12 |  | 0le0 | ⊢ 0  ≤  0 | 
						
							| 13 | 12 | a1i | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  0  ≤  0 ) | 
						
							| 14 |  | simpr | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  𝑎  ≤  𝑏 ) | 
						
							| 15 |  | icossico | ⊢ ( ( ( 0  ∈  ℝ*  ∧  𝑏  ∈  ℝ* )  ∧  ( 0  ≤  0  ∧  𝑎  ≤  𝑏 ) )  →  ( 0 [,) 𝑎 )  ⊆  ( 0 [,) 𝑏 ) ) | 
						
							| 16 | 9 11 13 14 15 | syl22anc | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  ( 0 [,) 𝑎 )  ⊆  ( 0 [,) 𝑏 ) ) | 
						
							| 17 |  | imass2 | ⊢ ( ( 0 [,) 𝑎 )  ⊆  ( 0 [,) 𝑏 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 18 | 16 17 | syl | ⊢ ( ( 𝑏  ∈  ℝ  ∧  𝑎  ≤  𝑏 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 19 | 7 18 | sylancom | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 20 |  | simplrl | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 21 |  | simplrr | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 22 | 19 20 21 | 3sstr4d | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  𝐴  ⊆  𝐵 ) | 
						
							| 23 | 22 | orcd | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑎  ≤  𝑏 )  →  ( 𝐴  ⊆  𝐵  ∨  𝐵  ⊆  𝐴 ) ) | 
						
							| 24 |  | simplll | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  𝑎  ∈  ℝ+ ) | 
						
							| 25 | 24 | rpred | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  𝑎  ∈  ℝ ) | 
						
							| 26 | 8 | a1i | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  0  ∈  ℝ* ) | 
						
							| 27 |  | simpl | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  𝑎  ∈  ℝ ) | 
						
							| 28 | 27 | rexrd | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  𝑎  ∈  ℝ* ) | 
						
							| 29 | 12 | a1i | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  0  ≤  0 ) | 
						
							| 30 |  | simpr | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  𝑏  ≤  𝑎 ) | 
						
							| 31 |  | icossico | ⊢ ( ( ( 0  ∈  ℝ*  ∧  𝑎  ∈  ℝ* )  ∧  ( 0  ≤  0  ∧  𝑏  ≤  𝑎 ) )  →  ( 0 [,) 𝑏 )  ⊆  ( 0 [,) 𝑎 ) ) | 
						
							| 32 | 26 28 29 30 31 | syl22anc | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  ( 0 [,) 𝑏 )  ⊆  ( 0 [,) 𝑎 ) ) | 
						
							| 33 |  | imass2 | ⊢ ( ( 0 [,) 𝑏 )  ⊆  ( 0 [,) 𝑎 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 34 | 32 33 | syl | ⊢ ( ( 𝑎  ∈  ℝ  ∧  𝑏  ≤  𝑎 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 35 | 25 34 | sylancom | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) )  ⊆  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 36 |  | simplrr | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 37 |  | simplrl | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 38 | 35 36 37 | 3sstr4d | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  𝐵  ⊆  𝐴 ) | 
						
							| 39 | 38 | olcd | ⊢ ( ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  ∧  𝑏  ≤  𝑎 )  →  ( 𝐴  ⊆  𝐵  ∨  𝐵  ⊆  𝐴 ) ) | 
						
							| 40 | 3 5 23 39 | lecasei | ⊢ ( ( ( 𝑎  ∈  ℝ+  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  ( 𝐴  ⊆  𝐵  ∨  𝐵  ⊆  𝐴 ) ) | 
						
							| 41 | 40 | adantlll | ⊢ ( ( ( ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹  ∧  𝐵  ∈  𝐹 )  ∧  𝑎  ∈  ℝ+ )  ∧  𝑏  ∈  ℝ+ )  ∧  ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) )  →  ( 𝐴  ⊆  𝐵  ∨  𝐵  ⊆  𝐴 ) ) | 
						
							| 42 | 1 | metustel | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  ( 𝐴  ∈  𝐹  ↔  ∃ 𝑎  ∈  ℝ+ 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) ) | 
						
							| 43 | 42 | biimpa | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  ∃ 𝑎  ∈  ℝ+ 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 44 | 43 | 3adant3 | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹  ∧  𝐵  ∈  𝐹 )  →  ∃ 𝑎  ∈  ℝ+ 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 45 |  | oveq2 | ⊢ ( 𝑎  =  𝑏  →  ( 0 [,) 𝑎 )  =  ( 0 [,) 𝑏 ) ) | 
						
							| 46 | 45 | imaeq2d | ⊢ ( 𝑎  =  𝑏  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 47 | 46 | cbvmptv | ⊢ ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) )  =  ( 𝑏  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 48 | 47 | rneqi | ⊢ ran  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) )  =  ran  ( 𝑏  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 49 | 1 48 | eqtri | ⊢ 𝐹  =  ran  ( 𝑏  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 50 | 49 | metustel | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  ( 𝐵  ∈  𝐹  ↔  ∃ 𝑏  ∈  ℝ+ 𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) ) | 
						
							| 51 | 50 | biimpa | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐵  ∈  𝐹 )  →  ∃ 𝑏  ∈  ℝ+ 𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 52 | 51 | 3adant2 | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹  ∧  𝐵  ∈  𝐹 )  →  ∃ 𝑏  ∈  ℝ+ 𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) | 
						
							| 53 |  | reeanv | ⊢ ( ∃ 𝑎  ∈  ℝ+ ∃ 𝑏  ∈  ℝ+ ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) )  ↔  ( ∃ 𝑎  ∈  ℝ+ 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  ∃ 𝑏  ∈  ℝ+ 𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) ) | 
						
							| 54 | 44 52 53 | sylanbrc | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹  ∧  𝐵  ∈  𝐹 )  →  ∃ 𝑎  ∈  ℝ+ ∃ 𝑏  ∈  ℝ+ ( 𝐴  =  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∧  𝐵  =  ( ◡ 𝐷  “  ( 0 [,) 𝑏 ) ) ) ) | 
						
							| 55 | 41 54 | r19.29vva | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹  ∧  𝐵  ∈  𝐹 )  →  ( 𝐴  ⊆  𝐵  ∨  𝐵  ⊆  𝐴 ) ) |