| Step | Hyp | Ref | Expression | 
						
							| 1 |  | metust.1 | ⊢ 𝐹  =  ran  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 2 |  | cnvimass | ⊢ ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  dom  𝐷 | 
						
							| 3 |  | psmetf | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  𝐷 : ( 𝑋  ×  𝑋 ) ⟶ ℝ* ) | 
						
							| 4 | 2 3 | fssdm | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( 𝑋  ×  𝑋 ) ) | 
						
							| 5 | 4 | ad2antrr | ⊢ ( ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  ∧  𝑎  ∈  ℝ+ )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( 𝑋  ×  𝑋 ) ) | 
						
							| 6 |  | cnvexg | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  ◡ 𝐷  ∈  V ) | 
						
							| 7 |  | imaexg | ⊢ ( ◡ 𝐷  ∈  V  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  V ) | 
						
							| 8 |  | elpwg | ⊢ ( ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  V  →  ( ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 )  ↔  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( 𝑋  ×  𝑋 ) ) ) | 
						
							| 9 | 6 7 8 | 3syl | ⊢ ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  →  ( ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 )  ↔  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( 𝑋  ×  𝑋 ) ) ) | 
						
							| 10 | 9 | ad2antrr | ⊢ ( ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  ∧  𝑎  ∈  ℝ+ )  →  ( ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 )  ↔  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ⊆  ( 𝑋  ×  𝑋 ) ) ) | 
						
							| 11 | 5 10 | mpbird | ⊢ ( ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  ∧  𝑎  ∈  ℝ+ )  →  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 12 | 11 | ralrimiva | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  ∀ 𝑎  ∈  ℝ+ ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 13 |  | eqid | ⊢ ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) )  =  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) ) | 
						
							| 14 | 13 | rnmptss | ⊢ ( ∀ 𝑎  ∈  ℝ+ ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) )  ∈  𝒫  ( 𝑋  ×  𝑋 )  →  ran  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) )  ⊆  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 15 | 12 14 | syl | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  ran  ( 𝑎  ∈  ℝ+  ↦  ( ◡ 𝐷  “  ( 0 [,) 𝑎 ) ) )  ⊆  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 16 | 1 15 | eqsstrid | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  𝐹  ⊆  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 17 |  | simpr | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  𝐴  ∈  𝐹 ) | 
						
							| 18 | 16 17 | sseldd | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  𝐴  ∈  𝒫  ( 𝑋  ×  𝑋 ) ) | 
						
							| 19 | 18 | elpwid | ⊢ ( ( 𝐷  ∈  ( PsMet ‘ 𝑋 )  ∧  𝐴  ∈  𝐹 )  →  𝐴  ⊆  ( 𝑋  ×  𝑋 ) ) |