| Step | Hyp | Ref | Expression | 
						
							| 1 |  | pi1co.p |  |-  P = ( J pi1 A ) | 
						
							| 2 |  | pi1co.q |  |-  Q = ( K pi1 B ) | 
						
							| 3 |  | pi1co.v |  |-  V = ( Base ` P ) | 
						
							| 4 |  | pi1co.g |  |-  G = ran ( g e. U. V |-> <. [ g ] ( ~=ph ` J ) , [ ( F o. g ) ] ( ~=ph ` K ) >. ) | 
						
							| 5 |  | pi1co.j |  |-  ( ph -> J e. ( TopOn ` X ) ) | 
						
							| 6 |  | pi1co.f |  |-  ( ph -> F e. ( J Cn K ) ) | 
						
							| 7 |  | pi1co.a |  |-  ( ph -> A e. X ) | 
						
							| 8 |  | pi1co.b |  |-  ( ph -> ( F ` A ) = B ) | 
						
							| 9 |  | fvex |  |-  ( ~=ph ` J ) e. _V | 
						
							| 10 |  | ecexg |  |-  ( ( ~=ph ` J ) e. _V -> [ g ] ( ~=ph ` J ) e. _V ) | 
						
							| 11 | 9 10 | mp1i |  |-  ( ( ph /\ g e. U. V ) -> [ g ] ( ~=ph ` J ) e. _V ) | 
						
							| 12 |  | fvex |  |-  ( ~=ph ` K ) e. _V | 
						
							| 13 |  | ecexg |  |-  ( ( ~=ph ` K ) e. _V -> [ ( F o. g ) ] ( ~=ph ` K ) e. _V ) | 
						
							| 14 | 12 13 | mp1i |  |-  ( ( ph /\ g e. U. V ) -> [ ( F o. g ) ] ( ~=ph ` K ) e. _V ) | 
						
							| 15 |  | eceq1 |  |-  ( g = T -> [ g ] ( ~=ph ` J ) = [ T ] ( ~=ph ` J ) ) | 
						
							| 16 |  | coeq2 |  |-  ( g = T -> ( F o. g ) = ( F o. T ) ) | 
						
							| 17 | 16 | eceq1d |  |-  ( g = T -> [ ( F o. g ) ] ( ~=ph ` K ) = [ ( F o. T ) ] ( ~=ph ` K ) ) | 
						
							| 18 | 1 2 3 4 5 6 7 8 | pi1cof |  |-  ( ph -> G : V --> ( Base ` Q ) ) | 
						
							| 19 | 18 | ffund |  |-  ( ph -> Fun G ) | 
						
							| 20 | 4 11 14 15 17 19 | fliftval |  |-  ( ( ph /\ T e. U. V ) -> ( G ` [ T ] ( ~=ph ` J ) ) = [ ( F o. T ) ] ( ~=ph ` K ) ) |