| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cvmcov.1 | ⊢ 𝑆  =  ( 𝑘  ∈  𝐽  ↦  { 𝑠  ∈  ( 𝒫  𝐶  ∖  { ∅ } )  ∣  ( ∪  𝑠  =  ( ◡ 𝐹  “  𝑘 )  ∧  ∀ 𝑢  ∈  𝑠 ( ∀ 𝑣  ∈  ( 𝑠  ∖  { 𝑢 } ) ( 𝑢  ∩  𝑣 )  =  ∅  ∧  ( 𝐹  ↾  𝑢 )  ∈  ( ( 𝐶  ↾t  𝑢 ) Homeo ( 𝐽  ↾t  𝑘 ) ) ) ) } ) | 
						
							| 2 |  | cvmseu.1 | ⊢ 𝐵  =  ∪  𝐶 | 
						
							| 3 |  | cvmfolem.2 | ⊢ 𝑋  =  ∪  𝐽 | 
						
							| 4 |  | cvmcn | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  𝐹  ∈  ( 𝐶  Cn  𝐽 ) ) | 
						
							| 5 | 2 3 | cnf | ⊢ ( 𝐹  ∈  ( 𝐶  Cn  𝐽 )  →  𝐹 : 𝐵 ⟶ 𝑋 ) | 
						
							| 6 | 4 5 | syl | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  𝐹 : 𝐵 ⟶ 𝑋 ) | 
						
							| 7 | 1 3 | cvmcov | ⊢ ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑥  ∈  𝑋 )  →  ∃ 𝑧  ∈  𝐽 ( 𝑥  ∈  𝑧  ∧  ( 𝑆 ‘ 𝑧 )  ≠  ∅ ) ) | 
						
							| 8 | 7 | ex | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  ( 𝑥  ∈  𝑋  →  ∃ 𝑧  ∈  𝐽 ( 𝑥  ∈  𝑧  ∧  ( 𝑆 ‘ 𝑧 )  ≠  ∅ ) ) ) | 
						
							| 9 |  | n0 | ⊢ ( ( 𝑆 ‘ 𝑧 )  ≠  ∅  ↔  ∃ 𝑤 𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) | 
						
							| 10 | 1 | cvmsn0 | ⊢ ( 𝑤  ∈  ( 𝑆 ‘ 𝑧 )  →  𝑤  ≠  ∅ ) | 
						
							| 11 | 10 | ad2antll | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) )  →  𝑤  ≠  ∅ ) | 
						
							| 12 |  | n0 | ⊢ ( 𝑤  ≠  ∅  ↔  ∃ 𝑡 𝑡  ∈  𝑤 ) | 
						
							| 13 | 11 12 | sylib | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) )  →  ∃ 𝑡 𝑡  ∈  𝑤 ) | 
						
							| 14 |  | simprlr | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) | 
						
							| 15 | 1 | cvmsss | ⊢ ( 𝑤  ∈  ( 𝑆 ‘ 𝑧 )  →  𝑤  ⊆  𝐶 ) | 
						
							| 16 | 14 15 | syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑤  ⊆  𝐶 ) | 
						
							| 17 |  | simprr | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑡  ∈  𝑤 ) | 
						
							| 18 | 16 17 | sseldd | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑡  ∈  𝐶 ) | 
						
							| 19 |  | elssuni | ⊢ ( 𝑡  ∈  𝐶  →  𝑡  ⊆  ∪  𝐶 ) | 
						
							| 20 | 18 19 | syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑡  ⊆  ∪  𝐶 ) | 
						
							| 21 | 20 2 | sseqtrrdi | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑡  ⊆  𝐵 ) | 
						
							| 22 |  | simpll | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝐹  ∈  ( 𝐶  CovMap  𝐽 ) ) | 
						
							| 23 | 1 | cvmsf1o | ⊢ ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 )  ∧  𝑡  ∈  𝑤 )  →  ( 𝐹  ↾  𝑡 ) : 𝑡 –1-1-onto→ 𝑧 ) | 
						
							| 24 | 22 14 17 23 | syl3anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ( 𝐹  ↾  𝑡 ) : 𝑡 –1-1-onto→ 𝑧 ) | 
						
							| 25 |  | f1ocnv | ⊢ ( ( 𝐹  ↾  𝑡 ) : 𝑡 –1-1-onto→ 𝑧  →  ◡ ( 𝐹  ↾  𝑡 ) : 𝑧 –1-1-onto→ 𝑡 ) | 
						
							| 26 |  | f1of | ⊢ ( ◡ ( 𝐹  ↾  𝑡 ) : 𝑧 –1-1-onto→ 𝑡  →  ◡ ( 𝐹  ↾  𝑡 ) : 𝑧 ⟶ 𝑡 ) | 
						
							| 27 | 24 25 26 | 3syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ◡ ( 𝐹  ↾  𝑡 ) : 𝑧 ⟶ 𝑡 ) | 
						
							| 28 |  | simprll | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑥  ∈  𝑧 ) | 
						
							| 29 | 27 28 | ffvelcdmd | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 )  ∈  𝑡 ) | 
						
							| 30 | 21 29 | sseldd | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 )  ∈  𝐵 ) | 
						
							| 31 |  | f1ocnvfv2 | ⊢ ( ( ( 𝐹  ↾  𝑡 ) : 𝑡 –1-1-onto→ 𝑧  ∧  𝑥  ∈  𝑧 )  →  ( ( 𝐹  ↾  𝑡 ) ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) )  =  𝑥 ) | 
						
							| 32 | 24 28 31 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ( ( 𝐹  ↾  𝑡 ) ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) )  =  𝑥 ) | 
						
							| 33 |  | fvres | ⊢ ( ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 )  ∈  𝑡  →  ( ( 𝐹  ↾  𝑡 ) ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) )  =  ( 𝐹 ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) ) ) | 
						
							| 34 | 29 33 | syl | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ( ( 𝐹  ↾  𝑡 ) ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) )  =  ( 𝐹 ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) ) ) | 
						
							| 35 | 32 34 | eqtr3d | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  𝑥  =  ( 𝐹 ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) ) ) | 
						
							| 36 |  | fveq2 | ⊢ ( 𝑦  =  ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 )  →  ( 𝐹 ‘ 𝑦 )  =  ( 𝐹 ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) ) ) | 
						
							| 37 | 36 | rspceeqv | ⊢ ( ( ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 )  ∈  𝐵  ∧  𝑥  =  ( 𝐹 ‘ ( ◡ ( 𝐹  ↾  𝑡 ) ‘ 𝑥 ) ) )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 38 | 30 35 37 | syl2anc | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) )  ∧  𝑡  ∈  𝑤 ) )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 39 | 38 | expr | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) )  →  ( 𝑡  ∈  𝑤  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 40 | 39 | exlimdv | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) )  →  ( ∃ 𝑡 𝑡  ∈  𝑤  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 41 | 13 40 | mpd | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  ( 𝑥  ∈  𝑧  ∧  𝑤  ∈  ( 𝑆 ‘ 𝑧 ) ) )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 42 | 41 | expr | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  𝑥  ∈  𝑧 )  →  ( 𝑤  ∈  ( 𝑆 ‘ 𝑧 )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 43 | 42 | exlimdv | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  𝑥  ∈  𝑧 )  →  ( ∃ 𝑤 𝑤  ∈  ( 𝑆 ‘ 𝑧 )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 44 | 9 43 | biimtrid | ⊢ ( ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  ∧  𝑥  ∈  𝑧 )  →  ( ( 𝑆 ‘ 𝑧 )  ≠  ∅  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 45 | 44 | expimpd | ⊢ ( ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  ∧  𝑧  ∈  𝐽 )  →  ( ( 𝑥  ∈  𝑧  ∧  ( 𝑆 ‘ 𝑧 )  ≠  ∅ )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 46 | 45 | rexlimdva | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  ( ∃ 𝑧  ∈  𝐽 ( 𝑥  ∈  𝑧  ∧  ( 𝑆 ‘ 𝑧 )  ≠  ∅ )  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 47 | 8 46 | syld | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  ( 𝑥  ∈  𝑋  →  ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 48 | 47 | ralrimiv | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  ∀ 𝑥  ∈  𝑋 ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) | 
						
							| 49 |  | dffo3 | ⊢ ( 𝐹 : 𝐵 –onto→ 𝑋  ↔  ( 𝐹 : 𝐵 ⟶ 𝑋  ∧  ∀ 𝑥  ∈  𝑋 ∃ 𝑦  ∈  𝐵 𝑥  =  ( 𝐹 ‘ 𝑦 ) ) ) | 
						
							| 50 | 6 48 49 | sylanbrc | ⊢ ( 𝐹  ∈  ( 𝐶  CovMap  𝐽 )  →  𝐹 : 𝐵 –onto→ 𝑋 ) |