| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simpl3 | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝐵  ∈  ( fBas ‘ 𝑍 ) ) | 
						
							| 2 |  | ssfg | ⊢ ( 𝐵  ∈  ( fBas ‘ 𝑍 )  →  𝐵  ⊆  ( 𝑍 filGen 𝐵 ) ) | 
						
							| 3 | 1 2 | syl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝐵  ⊆  ( 𝑍 filGen 𝐵 ) ) | 
						
							| 4 | 3 | sseld | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑢  ∈  𝐵  →  𝑢  ∈  ( 𝑍 filGen 𝐵 ) ) ) | 
						
							| 5 |  | simpl2 | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝑌  ∈  𝑊 ) | 
						
							| 6 |  | simprr | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝐺 : 𝑍 ⟶ 𝑌 ) | 
						
							| 7 |  | eqid | ⊢ ( 𝑍 filGen 𝐵 )  =  ( 𝑍 filGen 𝐵 ) | 
						
							| 8 | 7 | imaelfm | ⊢ ( ( ( 𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 )  ∧  𝐺 : 𝑍 ⟶ 𝑌 )  ∧  𝑢  ∈  ( 𝑍 filGen 𝐵 ) )  →  ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) | 
						
							| 9 | 8 | ex | ⊢ ( ( 𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 )  ∧  𝐺 : 𝑍 ⟶ 𝑌 )  →  ( 𝑢  ∈  ( 𝑍 filGen 𝐵 )  →  ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) ) | 
						
							| 10 | 5 1 6 9 | syl3anc | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑢  ∈  ( 𝑍 filGen 𝐵 )  →  ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) ) | 
						
							| 11 | 4 10 | syld | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑢  ∈  𝐵  →  ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) ) | 
						
							| 12 | 11 | imp | ⊢ ( ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  ∧  𝑢  ∈  𝐵 )  →  ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) | 
						
							| 13 |  | imaeq2 | ⊢ ( 𝑡  =  ( 𝐺  “  𝑢 )  →  ( 𝐹  “  𝑡 )  =  ( 𝐹  “  ( 𝐺  “  𝑢 ) ) ) | 
						
							| 14 |  | imaco | ⊢ ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  =  ( 𝐹  “  ( 𝐺  “  𝑢 ) ) | 
						
							| 15 | 13 14 | eqtr4di | ⊢ ( 𝑡  =  ( 𝐺  “  𝑢 )  →  ( 𝐹  “  𝑡 )  =  ( ( 𝐹  ∘  𝐺 )  “  𝑢 ) ) | 
						
							| 16 | 15 | sseq1d | ⊢ ( 𝑡  =  ( 𝐺  “  𝑢 )  →  ( ( 𝐹  “  𝑡 )  ⊆  𝑠  ↔  ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 17 | 16 | rspcev | ⊢ ( ( ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∧  ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 )  →  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) | 
						
							| 18 | 17 | ex | ⊢ ( ( 𝐺  “  𝑢 )  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  →  ( ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠  →  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) | 
						
							| 19 | 12 18 | syl | ⊢ ( ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  ∧  𝑢  ∈  𝐵 )  →  ( ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠  →  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) | 
						
							| 20 | 19 | rexlimdva | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠  →  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) | 
						
							| 21 |  | elfm | ⊢ ( ( 𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 )  ∧  𝐺 : 𝑍 ⟶ 𝑌 )  →  ( 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ↔  ( 𝑡  ⊆  𝑌  ∧  ∃ 𝑢  ∈  𝐵 ( 𝐺  “  𝑢 )  ⊆  𝑡 ) ) ) | 
						
							| 22 | 5 1 6 21 | syl3anc | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ↔  ( 𝑡  ⊆  𝑌  ∧  ∃ 𝑢  ∈  𝐵 ( 𝐺  “  𝑢 )  ⊆  𝑡 ) ) ) | 
						
							| 23 |  | sstr2 | ⊢ ( ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  ( 𝐹  “  𝑡 )  →  ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 24 |  | imass2 | ⊢ ( ( 𝐺  “  𝑢 )  ⊆  𝑡  →  ( 𝐹  “  ( 𝐺  “  𝑢 ) )  ⊆  ( 𝐹  “  𝑡 ) ) | 
						
							| 25 | 14 24 | eqsstrid | ⊢ ( ( 𝐺  “  𝑢 )  ⊆  𝑡  →  ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  ( 𝐹  “  𝑡 ) ) | 
						
							| 26 | 23 25 | syl11 | ⊢ ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ( ( 𝐺  “  𝑢 )  ⊆  𝑡  →  ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 27 | 26 | reximdv | ⊢ ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ( ∃ 𝑢  ∈  𝐵 ( 𝐺  “  𝑢 )  ⊆  𝑡  →  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 28 | 27 | com12 | ⊢ ( ∃ 𝑢  ∈  𝐵 ( 𝐺  “  𝑢 )  ⊆  𝑡  →  ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 29 | 28 | adantl | ⊢ ( ( 𝑡  ⊆  𝑌  ∧  ∃ 𝑢  ∈  𝐵 ( 𝐺  “  𝑢 )  ⊆  𝑡 )  →  ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 30 | 22 29 | biimtrdi | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  →  ( ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) ) | 
						
							| 31 | 30 | rexlimdv | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠  →  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) | 
						
							| 32 | 20 31 | impbid | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠  ↔  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) | 
						
							| 33 | 32 | anbi2d | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 )  ↔  ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) ) | 
						
							| 34 |  | simpl1 | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝑋  ∈  𝑉 ) | 
						
							| 35 |  | fco | ⊢ ( ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 )  →  ( 𝐹  ∘  𝐺 ) : 𝑍 ⟶ 𝑋 ) | 
						
							| 36 | 35 | adantl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝐹  ∘  𝐺 ) : 𝑍 ⟶ 𝑋 ) | 
						
							| 37 |  | elfm | ⊢ ( ( 𝑋  ∈  𝑉  ∧  𝐵  ∈  ( fBas ‘ 𝑍 )  ∧  ( 𝐹  ∘  𝐺 ) : 𝑍 ⟶ 𝑋 )  →  ( 𝑠  ∈  ( ( 𝑋  FilMap  ( 𝐹  ∘  𝐺 ) ) ‘ 𝐵 )  ↔  ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) ) | 
						
							| 38 | 34 1 36 37 | syl3anc | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑠  ∈  ( ( 𝑋  FilMap  ( 𝐹  ∘  𝐺 ) ) ‘ 𝐵 )  ↔  ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑢  ∈  𝐵 ( ( 𝐹  ∘  𝐺 )  “  𝑢 )  ⊆  𝑠 ) ) ) | 
						
							| 39 |  | fmfil | ⊢ ( ( 𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 )  ∧  𝐺 : 𝑍 ⟶ 𝑌 )  →  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( Fil ‘ 𝑌 ) ) | 
						
							| 40 | 5 1 6 39 | syl3anc | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( Fil ‘ 𝑌 ) ) | 
						
							| 41 |  | filfbas | ⊢ ( ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( Fil ‘ 𝑌 )  →  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 42 | 40 41 | syl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( fBas ‘ 𝑌 ) ) | 
						
							| 43 |  | simprl | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  𝐹 : 𝑌 ⟶ 𝑋 ) | 
						
							| 44 |  | elfm | ⊢ ( ( 𝑋  ∈  𝑉  ∧  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 )  ∈  ( fBas ‘ 𝑌 )  ∧  𝐹 : 𝑌 ⟶ 𝑋 )  →  ( 𝑠  ∈  ( ( 𝑋  FilMap  𝐹 ) ‘ ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) )  ↔  ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) ) | 
						
							| 45 | 34 42 43 44 | syl3anc | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑠  ∈  ( ( 𝑋  FilMap  𝐹 ) ‘ ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) )  ↔  ( 𝑠  ⊆  𝑋  ∧  ∃ 𝑡  ∈  ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ( 𝐹  “  𝑡 )  ⊆  𝑠 ) ) ) | 
						
							| 46 | 33 38 45 | 3bitr4d | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( 𝑠  ∈  ( ( 𝑋  FilMap  ( 𝐹  ∘  𝐺 ) ) ‘ 𝐵 )  ↔  𝑠  ∈  ( ( 𝑋  FilMap  𝐹 ) ‘ ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) ) ) | 
						
							| 47 | 46 | eqrdv | ⊢ ( ( ( 𝑋  ∈  𝑉  ∧  𝑌  ∈  𝑊  ∧  𝐵  ∈  ( fBas ‘ 𝑍 ) )  ∧  ( 𝐹 : 𝑌 ⟶ 𝑋  ∧  𝐺 : 𝑍 ⟶ 𝑌 ) )  →  ( ( 𝑋  FilMap  ( 𝐹  ∘  𝐺 ) ) ‘ 𝐵 )  =  ( ( 𝑋  FilMap  𝐹 ) ‘ ( ( 𝑌  FilMap  𝐺 ) ‘ 𝐵 ) ) ) |