| Step | Hyp | Ref | Expression | 
						
							| 1 |  | opbrop.1 |  |-  ( ( ( z = A /\ w = B ) /\ ( v = C /\ u = D ) ) -> ( ph <-> ps ) ) | 
						
							| 2 |  | opbrop.2 |  |-  R = { <. x , y >. | ( ( x e. ( S X. S ) /\ y e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( x = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) } | 
						
							| 3 |  | opelxpi |  |-  ( ( A e. S /\ B e. S ) -> <. A , B >. e. ( S X. S ) ) | 
						
							| 4 |  | opelxpi |  |-  ( ( C e. S /\ D e. S ) -> <. C , D >. e. ( S X. S ) ) | 
						
							| 5 | 3 4 | anim12i |  |-  ( ( ( A e. S /\ B e. S ) /\ ( C e. S /\ D e. S ) ) -> ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) ) | 
						
							| 6 |  | opex |  |-  <. A , B >. e. _V | 
						
							| 7 |  | opex |  |-  <. C , D >. e. _V | 
						
							| 8 |  | eleq1 |  |-  ( x = <. A , B >. -> ( x e. ( S X. S ) <-> <. A , B >. e. ( S X. S ) ) ) | 
						
							| 9 | 8 | anbi1d |  |-  ( x = <. A , B >. -> ( ( x e. ( S X. S ) /\ y e. ( S X. S ) ) <-> ( <. A , B >. e. ( S X. S ) /\ y e. ( S X. S ) ) ) ) | 
						
							| 10 |  | eqeq1 |  |-  ( x = <. A , B >. -> ( x = <. z , w >. <-> <. A , B >. = <. z , w >. ) ) | 
						
							| 11 | 10 | anbi1d |  |-  ( x = <. A , B >. -> ( ( x = <. z , w >. /\ y = <. v , u >. ) <-> ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) ) ) | 
						
							| 12 | 11 | anbi1d |  |-  ( x = <. A , B >. -> ( ( ( x = <. z , w >. /\ y = <. v , u >. ) /\ ph ) <-> ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) ) | 
						
							| 13 | 12 | 4exbidv |  |-  ( x = <. A , B >. -> ( E. z E. w E. v E. u ( ( x = <. z , w >. /\ y = <. v , u >. ) /\ ph ) <-> E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) ) | 
						
							| 14 | 9 13 | anbi12d |  |-  ( x = <. A , B >. -> ( ( ( x e. ( S X. S ) /\ y e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( x = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) <-> ( ( <. A , B >. e. ( S X. S ) /\ y e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) ) ) | 
						
							| 15 |  | eleq1 |  |-  ( y = <. C , D >. -> ( y e. ( S X. S ) <-> <. C , D >. e. ( S X. S ) ) ) | 
						
							| 16 | 15 | anbi2d |  |-  ( y = <. C , D >. -> ( ( <. A , B >. e. ( S X. S ) /\ y e. ( S X. S ) ) <-> ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) ) ) | 
						
							| 17 |  | eqeq1 |  |-  ( y = <. C , D >. -> ( y = <. v , u >. <-> <. C , D >. = <. v , u >. ) ) | 
						
							| 18 | 17 | anbi2d |  |-  ( y = <. C , D >. -> ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) <-> ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) ) ) | 
						
							| 19 | 18 | anbi1d |  |-  ( y = <. C , D >. -> ( ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) <-> ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) ) ) | 
						
							| 20 | 19 | 4exbidv |  |-  ( y = <. C , D >. -> ( E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) <-> E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) ) ) | 
						
							| 21 | 16 20 | anbi12d |  |-  ( y = <. C , D >. -> ( ( ( <. A , B >. e. ( S X. S ) /\ y e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ y = <. v , u >. ) /\ ph ) ) <-> ( ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) ) ) ) | 
						
							| 22 | 6 7 14 21 2 | brab |  |-  ( <. A , B >. R <. C , D >. <-> ( ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) ) ) | 
						
							| 23 | 1 | copsex4g |  |-  ( ( ( A e. S /\ B e. S ) /\ ( C e. S /\ D e. S ) ) -> ( E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) <-> ps ) ) | 
						
							| 24 | 23 | anbi2d |  |-  ( ( ( A e. S /\ B e. S ) /\ ( C e. S /\ D e. S ) ) -> ( ( ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) /\ E. z E. w E. v E. u ( ( <. A , B >. = <. z , w >. /\ <. C , D >. = <. v , u >. ) /\ ph ) ) <-> ( ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) /\ ps ) ) ) | 
						
							| 25 | 22 24 | bitrid |  |-  ( ( ( A e. S /\ B e. S ) /\ ( C e. S /\ D e. S ) ) -> ( <. A , B >. R <. C , D >. <-> ( ( <. A , B >. e. ( S X. S ) /\ <. C , D >. e. ( S X. S ) ) /\ ps ) ) ) | 
						
							| 26 | 5 25 | mpbirand |  |-  ( ( ( A e. S /\ B e. S ) /\ ( C e. S /\ D e. S ) ) -> ( <. A , B >. R <. C , D >. <-> ps ) ) |