| Step | Hyp | Ref | Expression | 
						
							| 1 |  | copsex2d.xph |  |-  ( ph -> A. x ph ) | 
						
							| 2 |  | copsex2d.yph |  |-  ( ph -> A. y ph ) | 
						
							| 3 |  | copsex2d.xch |  |-  ( ph -> F/ x ch ) | 
						
							| 4 |  | copsex2d.ych |  |-  ( ph -> F/ y ch ) | 
						
							| 5 |  | copsex2d.exa |  |-  ( ph -> A e. U ) | 
						
							| 6 |  | copsex2d.exb |  |-  ( ph -> B e. V ) | 
						
							| 7 |  | copsex2d.is |  |-  ( ( ph /\ ( x = A /\ y = B ) ) -> ( ps <-> ch ) ) | 
						
							| 8 |  | elisset |  |-  ( A e. U -> E. x x = A ) | 
						
							| 9 | 5 8 | syl |  |-  ( ph -> E. x x = A ) | 
						
							| 10 |  | elisset |  |-  ( B e. V -> E. y y = B ) | 
						
							| 11 | 6 10 | syl |  |-  ( ph -> E. y y = B ) | 
						
							| 12 |  | exdistrv |  |-  ( E. x E. y ( x = A /\ y = B ) <-> ( E. x x = A /\ E. y y = B ) ) | 
						
							| 13 |  | nfe1 |  |-  F/ x E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) | 
						
							| 14 | 13 | a1i |  |-  ( ph -> F/ x E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) ) | 
						
							| 15 | 14 3 | nfbid |  |-  ( ph -> F/ x ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) | 
						
							| 16 | 15 | 19.9d |  |-  ( ph -> ( E. x ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 17 |  | nfe1 |  |-  F/ y E. y ( <. A , B >. = <. x , y >. /\ ps ) | 
						
							| 18 | 17 | a1i |  |-  ( ph -> F/ y E. y ( <. A , B >. = <. x , y >. /\ ps ) ) | 
						
							| 19 | 1 18 | bj-nfexd |  |-  ( ph -> F/ y E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) ) | 
						
							| 20 | 19 4 | nfbid |  |-  ( ph -> F/ y ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) | 
						
							| 21 | 20 | 19.9d |  |-  ( ph -> ( E. y ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 22 |  | opeq12 |  |-  ( ( x = A /\ y = B ) -> <. x , y >. = <. A , B >. ) | 
						
							| 23 |  | copsexgw |  |-  ( <. A , B >. = <. x , y >. -> ( ps <-> E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) ) ) | 
						
							| 24 | 23 | bicomd |  |-  ( <. A , B >. = <. x , y >. -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ps ) ) | 
						
							| 25 | 24 | eqcoms |  |-  ( <. x , y >. = <. A , B >. -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ps ) ) | 
						
							| 26 | 22 25 | syl |  |-  ( ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ps ) ) | 
						
							| 27 | 26 | adantl |  |-  ( ( ph /\ ( x = A /\ y = B ) ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ps ) ) | 
						
							| 28 | 27 7 | bitrd |  |-  ( ( ph /\ ( x = A /\ y = B ) ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) | 
						
							| 29 | 28 | ex |  |-  ( ph -> ( ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 30 | 2 21 29 | bj-exlimd |  |-  ( ph -> ( E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 31 | 1 16 30 | bj-exlimd |  |-  ( ph -> ( E. x E. y ( x = A /\ y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 32 | 12 31 | biimtrrid |  |-  ( ph -> ( ( E. x x = A /\ E. y y = B ) -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) ) | 
						
							| 33 | 9 11 32 | mp2and |  |-  ( ph -> ( E. x E. y ( <. A , B >. = <. x , y >. /\ ps ) <-> ch ) ) |