| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpll | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 2 |  | fgcl | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑌 )  →  ( 𝑌 filGen 𝐹 )  ∈  ( Fil ‘ 𝑌 ) ) | 
						
							| 3 |  | filfbas | ⊢ ( ( 𝑌 filGen 𝐹 )  ∈  ( Fil ‘ 𝑌 )  →  ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 4 | 1 2 3 | 3syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 5 |  | fbsspw | ⊢ ( ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑌 )  →  ( 𝑌 filGen 𝐹 )  ⊆  𝒫  𝑌 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑌 filGen 𝐹 )  ⊆  𝒫  𝑌 ) | 
						
							| 7 |  | simplr | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝑌  ⊆  𝑋 ) | 
						
							| 8 | 7 | sspwd | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝒫  𝑌  ⊆  𝒫  𝑋 ) | 
						
							| 9 | 6 8 | sstrd | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑌 filGen 𝐹 )  ⊆  𝒫  𝑋 ) | 
						
							| 10 |  | simpr | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝑋  ∈  V ) | 
						
							| 11 |  | fbasweak | ⊢ ( ( ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑌 )  ∧  ( 𝑌 filGen 𝐹 )  ⊆  𝒫  𝑋  ∧  𝑋  ∈  V )  →  ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑋 ) ) | 
						
							| 12 | 4 9 10 11 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑋 ) ) | 
						
							| 13 |  | elfg | ⊢ ( ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑋 )  →  ( 𝑥  ∈  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  ↔  ( 𝑥  ⊆  𝑋  ∧  ∃ 𝑦  ∈  ( 𝑌 filGen 𝐹 ) 𝑦  ⊆  𝑥 ) ) ) | 
						
							| 14 | 12 13 | syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑥  ∈  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  ↔  ( 𝑥  ⊆  𝑋  ∧  ∃ 𝑦  ∈  ( 𝑌 filGen 𝐹 ) 𝑦  ⊆  𝑥 ) ) ) | 
						
							| 15 | 1 | adantr | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  →  𝐹  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 16 |  | elfg | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑌 )  →  ( 𝑦  ∈  ( 𝑌 filGen 𝐹 )  ↔  ( 𝑦  ⊆  𝑌  ∧  ∃ 𝑧  ∈  𝐹 𝑧  ⊆  𝑦 ) ) ) | 
						
							| 17 | 15 16 | syl | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  →  ( 𝑦  ∈  ( 𝑌 filGen 𝐹 )  ↔  ( 𝑦  ⊆  𝑌  ∧  ∃ 𝑧  ∈  𝐹 𝑧  ⊆  𝑦 ) ) ) | 
						
							| 18 |  | fbsspw | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑌 )  →  𝐹  ⊆  𝒫  𝑌 ) | 
						
							| 19 | 1 18 | syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ⊆  𝒫  𝑌 ) | 
						
							| 20 | 19 8 | sstrd | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ⊆  𝒫  𝑋 ) | 
						
							| 21 |  | fbasweak | ⊢ ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝐹  ⊆  𝒫  𝑋  ∧  𝑋  ∈  V )  →  𝐹  ∈  ( fBas ‘ 𝑋 ) ) | 
						
							| 22 | 1 20 10 21 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ∈  ( fBas ‘ 𝑋 ) ) | 
						
							| 23 |  | fgcl | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑋 )  →  ( 𝑋 filGen 𝐹 )  ∈  ( Fil ‘ 𝑋 ) ) | 
						
							| 24 | 22 23 | syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑋 filGen 𝐹 )  ∈  ( Fil ‘ 𝑋 ) ) | 
						
							| 25 | 24 | ad2antrr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  ( 𝑋 filGen 𝐹 )  ∈  ( Fil ‘ 𝑋 ) ) | 
						
							| 26 |  | ssfg | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑋 )  →  𝐹  ⊆  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 27 | 22 26 | syl | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ⊆  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 28 | 27 | adantr | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  →  𝐹  ⊆  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 29 | 28 | sselda | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  𝑧  ∈  𝐹 )  →  𝑧  ∈  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 30 | 29 | adantrr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 ) )  →  𝑧  ∈  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 31 | 30 | adantrr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑧  ∈  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 32 |  | simplrl | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑥  ⊆  𝑋 ) | 
						
							| 33 |  | simprlr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑧  ⊆  𝑦 ) | 
						
							| 34 |  | simprr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑦  ⊆  𝑥 ) | 
						
							| 35 | 33 34 | sstrd | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑧  ⊆  𝑥 ) | 
						
							| 36 |  | filss | ⊢ ( ( ( 𝑋 filGen 𝐹 )  ∈  ( Fil ‘ 𝑋 )  ∧  ( 𝑧  ∈  ( 𝑋 filGen 𝐹 )  ∧  𝑥  ⊆  𝑋  ∧  𝑧  ⊆  𝑥 ) )  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 37 | 25 31 32 35 36 | syl13anc | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 )  ∧  𝑦  ⊆  𝑥 ) )  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 38 | 37 | expr | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  ∧  ( 𝑧  ∈  𝐹  ∧  𝑧  ⊆  𝑦 ) )  →  ( 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) | 
						
							| 39 | 38 | rexlimdvaa | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  ( 𝑥  ⊆  𝑋  ∧  𝑦  ⊆  𝑌 ) )  →  ( ∃ 𝑧  ∈  𝐹 𝑧  ⊆  𝑦  →  ( 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) ) | 
						
							| 40 | 39 | anassrs | ⊢ ( ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  ∧  𝑦  ⊆  𝑌 )  →  ( ∃ 𝑧  ∈  𝐹 𝑧  ⊆  𝑦  →  ( 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) ) | 
						
							| 41 | 40 | expimpd | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  →  ( ( 𝑦  ⊆  𝑌  ∧  ∃ 𝑧  ∈  𝐹 𝑧  ⊆  𝑦 )  →  ( 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) ) | 
						
							| 42 | 17 41 | sylbid | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  →  ( 𝑦  ∈  ( 𝑌 filGen 𝐹 )  →  ( 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) ) | 
						
							| 43 | 42 | rexlimdv | ⊢ ( ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  ∧  𝑥  ⊆  𝑋 )  →  ( ∃ 𝑦  ∈  ( 𝑌 filGen 𝐹 ) 𝑦  ⊆  𝑥  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) | 
						
							| 44 | 43 | expimpd | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( ( 𝑥  ⊆  𝑋  ∧  ∃ 𝑦  ∈  ( 𝑌 filGen 𝐹 ) 𝑦  ⊆  𝑥 )  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) | 
						
							| 45 | 14 44 | sylbid | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑥  ∈  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  →  𝑥  ∈  ( 𝑋 filGen 𝐹 ) ) ) | 
						
							| 46 | 45 | ssrdv | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  ⊆  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 47 |  | ssfg | ⊢ ( 𝐹  ∈  ( fBas ‘ 𝑌 )  →  𝐹  ⊆  ( 𝑌 filGen 𝐹 ) ) | 
						
							| 48 | 47 | ad2antrr | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  𝐹  ⊆  ( 𝑌 filGen 𝐹 ) ) | 
						
							| 49 |  | fgss | ⊢ ( ( 𝐹  ∈  ( fBas ‘ 𝑋 )  ∧  ( 𝑌 filGen 𝐹 )  ∈  ( fBas ‘ 𝑋 )  ∧  𝐹  ⊆  ( 𝑌 filGen 𝐹 ) )  →  ( 𝑋 filGen 𝐹 )  ⊆  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) ) ) | 
						
							| 50 | 22 12 48 49 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑋 filGen 𝐹 )  ⊆  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) ) ) | 
						
							| 51 | 46 50 | eqssd | ⊢ ( ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  ∧  𝑋  ∈  V )  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  =  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 52 | 51 | ex | ⊢ ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  →  ( 𝑋  ∈  V  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  =  ( 𝑋 filGen 𝐹 ) ) ) | 
						
							| 53 |  | df-fg | ⊢ filGen  =  ( 𝑤  ∈  V ,  𝑥  ∈  ( fBas ‘ 𝑤 )  ↦  { 𝑦  ∈  𝒫  𝑤  ∣  ( 𝑥  ∩  𝒫  𝑦 )  ≠  ∅ } ) | 
						
							| 54 | 53 | reldmmpo | ⊢ Rel  dom  filGen | 
						
							| 55 | 54 | ovprc1 | ⊢ ( ¬  𝑋  ∈  V  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  =  ∅ ) | 
						
							| 56 | 54 | ovprc1 | ⊢ ( ¬  𝑋  ∈  V  →  ( 𝑋 filGen 𝐹 )  =  ∅ ) | 
						
							| 57 | 55 56 | eqtr4d | ⊢ ( ¬  𝑋  ∈  V  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  =  ( 𝑋 filGen 𝐹 ) ) | 
						
							| 58 | 52 57 | pm2.61d1 | ⊢ ( ( 𝐹  ∈  ( fBas ‘ 𝑌 )  ∧  𝑌  ⊆  𝑋 )  →  ( 𝑋 filGen ( 𝑌 filGen 𝐹 ) )  =  ( 𝑋 filGen 𝐹 ) ) |