| Step | Hyp | Ref | Expression | 
						
							| 1 |  | fvssunirn | ⊢ ( ∞Met ‘ 𝑋 )  ⊆  ∪  ran  ∞Met | 
						
							| 2 | 1 | sseli | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  𝐷  ∈  ∪  ran  ∞Met ) | 
						
							| 3 |  | dmeq | ⊢ ( 𝑑  =  𝐷  →  dom  𝑑  =  dom  𝐷 ) | 
						
							| 4 | 3 | dmeqd | ⊢ ( 𝑑  =  𝐷  →  dom  dom  𝑑  =  dom  dom  𝐷 ) | 
						
							| 5 | 4 | fveq2d | ⊢ ( 𝑑  =  𝐷  →  ( Fil ‘ dom  dom  𝑑 )  =  ( Fil ‘ dom  dom  𝐷 ) ) | 
						
							| 6 |  | imaeq1 | ⊢ ( 𝑑  =  𝐷  →  ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  =  ( 𝐷  “  ( 𝑦  ×  𝑦 ) ) ) | 
						
							| 7 | 6 | sseq1d | ⊢ ( 𝑑  =  𝐷  →  ( ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 )  ↔  ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) ) ) | 
						
							| 8 | 7 | rexbidv | ⊢ ( 𝑑  =  𝐷  →  ( ∃ 𝑦  ∈  𝑓 ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 )  ↔  ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) ) ) | 
						
							| 9 | 8 | ralbidv | ⊢ ( 𝑑  =  𝐷  →  ( ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 )  ↔  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) ) ) | 
						
							| 10 | 5 9 | rabeqbidv | ⊢ ( 𝑑  =  𝐷  →  { 𝑓  ∈  ( Fil ‘ dom  dom  𝑑 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) }  =  { 𝑓  ∈  ( Fil ‘ dom  dom  𝐷 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) | 
						
							| 11 |  | df-cfil | ⊢ CauFil  =  ( 𝑑  ∈  ∪  ran  ∞Met  ↦  { 𝑓  ∈  ( Fil ‘ dom  dom  𝑑 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝑑  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) | 
						
							| 12 |  | fvex | ⊢ ( Fil ‘ dom  dom  𝐷 )  ∈  V | 
						
							| 13 | 12 | rabex | ⊢ { 𝑓  ∈  ( Fil ‘ dom  dom  𝐷 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) }  ∈  V | 
						
							| 14 | 10 11 13 | fvmpt | ⊢ ( 𝐷  ∈  ∪  ran  ∞Met  →  ( CauFil ‘ 𝐷 )  =  { 𝑓  ∈  ( Fil ‘ dom  dom  𝐷 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) | 
						
							| 15 | 2 14 | syl | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  ( CauFil ‘ 𝐷 )  =  { 𝑓  ∈  ( Fil ‘ dom  dom  𝐷 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) | 
						
							| 16 |  | xmetdmdm | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  𝑋  =  dom  dom  𝐷 ) | 
						
							| 17 | 16 | fveq2d | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  ( Fil ‘ 𝑋 )  =  ( Fil ‘ dom  dom  𝐷 ) ) | 
						
							| 18 | 17 | rabeqdv | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  { 𝑓  ∈  ( Fil ‘ 𝑋 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) }  =  { 𝑓  ∈  ( Fil ‘ dom  dom  𝐷 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) | 
						
							| 19 | 15 18 | eqtr4d | ⊢ ( 𝐷  ∈  ( ∞Met ‘ 𝑋 )  →  ( CauFil ‘ 𝐷 )  =  { 𝑓  ∈  ( Fil ‘ 𝑋 )  ∣  ∀ 𝑥  ∈  ℝ+ ∃ 𝑦  ∈  𝑓 ( 𝐷  “  ( 𝑦  ×  𝑦 ) )  ⊆  ( 0 [,) 𝑥 ) } ) |