| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid | ⊢ ∪  𝐾  =  ∪  𝐾 | 
						
							| 2 | 1 | flimelbas | ⊢ ( 𝑥  ∈  ( 𝐾  fLim  𝐹 )  →  𝑥  ∈  ∪  𝐾 ) | 
						
							| 3 | 2 | adantl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝑥  ∈  ∪  𝐾 ) | 
						
							| 4 |  | simpl2 | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐹  ∈  ( Fil ‘ 𝑋 ) ) | 
						
							| 5 |  | filunibas | ⊢ ( 𝐹  ∈  ( Fil ‘ 𝑋 )  →  ∪  𝐹  =  𝑋 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ∪  𝐹  =  𝑋 ) | 
						
							| 7 | 1 | flimfil | ⊢ ( 𝑥  ∈  ( 𝐾  fLim  𝐹 )  →  𝐹  ∈  ( Fil ‘ ∪  𝐾 ) ) | 
						
							| 8 | 7 | adantl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐹  ∈  ( Fil ‘ ∪  𝐾 ) ) | 
						
							| 9 |  | filunibas | ⊢ ( 𝐹  ∈  ( Fil ‘ ∪  𝐾 )  →  ∪  𝐹  =  ∪  𝐾 ) | 
						
							| 10 | 8 9 | syl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ∪  𝐹  =  ∪  𝐾 ) | 
						
							| 11 | 6 10 | eqtr3d | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝑋  =  ∪  𝐾 ) | 
						
							| 12 | 3 11 | eleqtrrd | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝑥  ∈  𝑋 ) | 
						
							| 13 |  | simpl1 | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐽  ∈  ( TopOn ‘ 𝑋 ) ) | 
						
							| 14 |  | topontop | ⊢ ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  →  𝐽  ∈  Top ) | 
						
							| 15 | 13 14 | syl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐽  ∈  Top ) | 
						
							| 16 |  | flimtop | ⊢ ( 𝑥  ∈  ( 𝐾  fLim  𝐹 )  →  𝐾  ∈  Top ) | 
						
							| 17 | 16 | adantl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐾  ∈  Top ) | 
						
							| 18 |  | toponuni | ⊢ ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  →  𝑋  =  ∪  𝐽 ) | 
						
							| 19 | 13 18 | syl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝑋  =  ∪  𝐽 ) | 
						
							| 20 | 19 11 | eqtr3d | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ∪  𝐽  =  ∪  𝐾 ) | 
						
							| 21 |  | simpl3 | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝐽  ⊆  𝐾 ) | 
						
							| 22 |  | eqid | ⊢ ∪  𝐽  =  ∪  𝐽 | 
						
							| 23 | 22 1 | topssnei | ⊢ ( ( ( 𝐽  ∈  Top  ∧  𝐾  ∈  Top  ∧  ∪  𝐽  =  ∪  𝐾 )  ∧  𝐽  ⊆  𝐾 )  →  ( ( nei ‘ 𝐽 ) ‘ { 𝑥 } )  ⊆  ( ( nei ‘ 𝐾 ) ‘ { 𝑥 } ) ) | 
						
							| 24 | 15 17 20 21 23 | syl31anc | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ( ( nei ‘ 𝐽 ) ‘ { 𝑥 } )  ⊆  ( ( nei ‘ 𝐾 ) ‘ { 𝑥 } ) ) | 
						
							| 25 |  | flimneiss | ⊢ ( 𝑥  ∈  ( 𝐾  fLim  𝐹 )  →  ( ( nei ‘ 𝐾 ) ‘ { 𝑥 } )  ⊆  𝐹 ) | 
						
							| 26 | 25 | adantl | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ( ( nei ‘ 𝐾 ) ‘ { 𝑥 } )  ⊆  𝐹 ) | 
						
							| 27 | 24 26 | sstrd | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ( ( nei ‘ 𝐽 ) ‘ { 𝑥 } )  ⊆  𝐹 ) | 
						
							| 28 |  | elflim | ⊢ ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 ) )  →  ( 𝑥  ∈  ( 𝐽  fLim  𝐹 )  ↔  ( 𝑥  ∈  𝑋  ∧  ( ( nei ‘ 𝐽 ) ‘ { 𝑥 } )  ⊆  𝐹 ) ) ) | 
						
							| 29 | 13 4 28 | syl2anc | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  ( 𝑥  ∈  ( 𝐽  fLim  𝐹 )  ↔  ( 𝑥  ∈  𝑋  ∧  ( ( nei ‘ 𝐽 ) ‘ { 𝑥 } )  ⊆  𝐹 ) ) ) | 
						
							| 30 | 12 27 29 | mpbir2and | ⊢ ( ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  ∧  𝑥  ∈  ( 𝐾  fLim  𝐹 ) )  →  𝑥  ∈  ( 𝐽  fLim  𝐹 ) ) | 
						
							| 31 | 30 | ex | ⊢ ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  →  ( 𝑥  ∈  ( 𝐾  fLim  𝐹 )  →  𝑥  ∈  ( 𝐽  fLim  𝐹 ) ) ) | 
						
							| 32 | 31 | ssrdv | ⊢ ( ( 𝐽  ∈  ( TopOn ‘ 𝑋 )  ∧  𝐹  ∈  ( Fil ‘ 𝑋 )  ∧  𝐽  ⊆  𝐾 )  →  ( 𝐾  fLim  𝐹 )  ⊆  ( 𝐽  fLim  𝐹 ) ) |