| Step | Hyp | Ref | Expression | 
						
							| 1 |  | comfeq.1 |  |-  .x. = ( comp ` C ) | 
						
							| 2 |  | comfeq.2 |  |-  .xb = ( comp ` D ) | 
						
							| 3 |  | comfeq.h |  |-  H = ( Hom ` C ) | 
						
							| 4 |  | comfeq.3 |  |-  ( ph -> B = ( Base ` C ) ) | 
						
							| 5 |  | comfeq.4 |  |-  ( ph -> B = ( Base ` D ) ) | 
						
							| 6 |  | comfeq.5 |  |-  ( ph -> ( Homf ` C ) = ( Homf ` D ) ) | 
						
							| 7 | 4 | sqxpeqd |  |-  ( ph -> ( B X. B ) = ( ( Base ` C ) X. ( Base ` C ) ) ) | 
						
							| 8 |  | eqidd |  |-  ( ph -> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) | 
						
							| 9 | 7 4 8 | mpoeq123dv |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( u e. ( ( Base ` C ) X. ( Base ` C ) ) , z e. ( Base ` C ) |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) ) | 
						
							| 10 |  | eqid |  |-  ( comf ` C ) = ( comf ` C ) | 
						
							| 11 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 12 | 10 11 3 1 | comfffval |  |-  ( comf ` C ) = ( u e. ( ( Base ` C ) X. ( Base ` C ) ) , z e. ( Base ` C ) |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) | 
						
							| 13 | 9 12 | eqtr4di |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( comf ` C ) ) | 
						
							| 14 |  | eqid |  |-  ( Hom ` D ) = ( Hom ` D ) | 
						
							| 15 | 6 | 3ad2ant1 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( Homf ` C ) = ( Homf ` D ) ) | 
						
							| 16 |  | xp2nd |  |-  ( u e. ( B X. B ) -> ( 2nd ` u ) e. B ) | 
						
							| 17 | 16 | 3ad2ant2 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( 2nd ` u ) e. B ) | 
						
							| 18 | 4 | 3ad2ant1 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> B = ( Base ` C ) ) | 
						
							| 19 | 17 18 | eleqtrd |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( 2nd ` u ) e. ( Base ` C ) ) | 
						
							| 20 |  | simp3 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> z e. B ) | 
						
							| 21 | 20 18 | eleqtrd |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> z e. ( Base ` C ) ) | 
						
							| 22 | 11 3 14 15 19 21 | homfeqval |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( ( 2nd ` u ) H z ) = ( ( 2nd ` u ) ( Hom ` D ) z ) ) | 
						
							| 23 |  | xp1st |  |-  ( u e. ( B X. B ) -> ( 1st ` u ) e. B ) | 
						
							| 24 | 23 | 3ad2ant2 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( 1st ` u ) e. B ) | 
						
							| 25 | 24 18 | eleqtrd |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( 1st ` u ) e. ( Base ` C ) ) | 
						
							| 26 | 11 3 14 15 25 19 | homfeqval |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( ( 1st ` u ) H ( 2nd ` u ) ) = ( ( 1st ` u ) ( Hom ` D ) ( 2nd ` u ) ) ) | 
						
							| 27 |  | df-ov |  |-  ( ( 1st ` u ) H ( 2nd ` u ) ) = ( H ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) | 
						
							| 28 |  | df-ov |  |-  ( ( 1st ` u ) ( Hom ` D ) ( 2nd ` u ) ) = ( ( Hom ` D ) ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) | 
						
							| 29 | 26 27 28 | 3eqtr3g |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( H ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) = ( ( Hom ` D ) ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) ) | 
						
							| 30 |  | 1st2nd2 |  |-  ( u e. ( B X. B ) -> u = <. ( 1st ` u ) , ( 2nd ` u ) >. ) | 
						
							| 31 | 30 | 3ad2ant2 |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> u = <. ( 1st ` u ) , ( 2nd ` u ) >. ) | 
						
							| 32 | 31 | fveq2d |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( H ` u ) = ( H ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) ) | 
						
							| 33 | 31 | fveq2d |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( ( Hom ` D ) ` u ) = ( ( Hom ` D ) ` <. ( 1st ` u ) , ( 2nd ` u ) >. ) ) | 
						
							| 34 | 29 32 33 | 3eqtr4d |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( H ` u ) = ( ( Hom ` D ) ` u ) ) | 
						
							| 35 |  | eqidd |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( g ( u .xb z ) f ) = ( g ( u .xb z ) f ) ) | 
						
							| 36 | 22 34 35 | mpoeq123dv |  |-  ( ( ph /\ u e. ( B X. B ) /\ z e. B ) -> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) = ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) | 
						
							| 37 | 36 | mpoeq3dva |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) = ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) ) | 
						
							| 38 | 5 | sqxpeqd |  |-  ( ph -> ( B X. B ) = ( ( Base ` D ) X. ( Base ` D ) ) ) | 
						
							| 39 |  | eqidd |  |-  ( ph -> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) = ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) | 
						
							| 40 | 38 5 39 | mpoeq123dv |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) = ( u e. ( ( Base ` D ) X. ( Base ` D ) ) , z e. ( Base ` D ) |-> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) ) | 
						
							| 41 | 37 40 | eqtrd |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) = ( u e. ( ( Base ` D ) X. ( Base ` D ) ) , z e. ( Base ` D ) |-> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) ) | 
						
							| 42 |  | eqid |  |-  ( comf ` D ) = ( comf ` D ) | 
						
							| 43 |  | eqid |  |-  ( Base ` D ) = ( Base ` D ) | 
						
							| 44 | 42 43 14 2 | comfffval |  |-  ( comf ` D ) = ( u e. ( ( Base ` D ) X. ( Base ` D ) ) , z e. ( Base ` D ) |-> ( g e. ( ( 2nd ` u ) ( Hom ` D ) z ) , f e. ( ( Hom ` D ) ` u ) |-> ( g ( u .xb z ) f ) ) ) | 
						
							| 45 | 41 44 | eqtr4di |  |-  ( ph -> ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) = ( comf ` D ) ) | 
						
							| 46 | 13 45 | eqeq12d |  |-  ( ph -> ( ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) <-> ( comf ` C ) = ( comf ` D ) ) ) | 
						
							| 47 |  | ovex |  |-  ( ( 2nd ` u ) H z ) e. _V | 
						
							| 48 |  | fvex |  |-  ( H ` u ) e. _V | 
						
							| 49 | 47 48 | mpoex |  |-  ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) e. _V | 
						
							| 50 | 49 | rgen2w |  |-  A. u e. ( B X. B ) A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) e. _V | 
						
							| 51 |  | mpo2eqb |  |-  ( A. u e. ( B X. B ) A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) e. _V -> ( ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) <-> A. u e. ( B X. B ) A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) ) | 
						
							| 52 | 50 51 | ax-mp |  |-  ( ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) <-> A. u e. ( B X. B ) A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) | 
						
							| 53 |  | vex |  |-  x e. _V | 
						
							| 54 |  | vex |  |-  y e. _V | 
						
							| 55 | 53 54 | op2ndd |  |-  ( u = <. x , y >. -> ( 2nd ` u ) = y ) | 
						
							| 56 | 55 | oveq1d |  |-  ( u = <. x , y >. -> ( ( 2nd ` u ) H z ) = ( y H z ) ) | 
						
							| 57 |  | fveq2 |  |-  ( u = <. x , y >. -> ( H ` u ) = ( H ` <. x , y >. ) ) | 
						
							| 58 |  | df-ov |  |-  ( x H y ) = ( H ` <. x , y >. ) | 
						
							| 59 | 57 58 | eqtr4di |  |-  ( u = <. x , y >. -> ( H ` u ) = ( x H y ) ) | 
						
							| 60 |  | oveq1 |  |-  ( u = <. x , y >. -> ( u .x. z ) = ( <. x , y >. .x. z ) ) | 
						
							| 61 | 60 | oveqd |  |-  ( u = <. x , y >. -> ( g ( u .x. z ) f ) = ( g ( <. x , y >. .x. z ) f ) ) | 
						
							| 62 |  | oveq1 |  |-  ( u = <. x , y >. -> ( u .xb z ) = ( <. x , y >. .xb z ) ) | 
						
							| 63 | 62 | oveqd |  |-  ( u = <. x , y >. -> ( g ( u .xb z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) | 
						
							| 64 | 61 63 | eqeq12d |  |-  ( u = <. x , y >. -> ( ( g ( u .x. z ) f ) = ( g ( u .xb z ) f ) <-> ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) | 
						
							| 65 | 59 64 | raleqbidv |  |-  ( u = <. x , y >. -> ( A. f e. ( H ` u ) ( g ( u .x. z ) f ) = ( g ( u .xb z ) f ) <-> A. f e. ( x H y ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) | 
						
							| 66 | 56 65 | raleqbidv |  |-  ( u = <. x , y >. -> ( A. g e. ( ( 2nd ` u ) H z ) A. f e. ( H ` u ) ( g ( u .x. z ) f ) = ( g ( u .xb z ) f ) <-> A. g e. ( y H z ) A. f e. ( x H y ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) | 
						
							| 67 |  | ovex |  |-  ( g ( u .x. z ) f ) e. _V | 
						
							| 68 | 67 | rgen2w |  |-  A. g e. ( ( 2nd ` u ) H z ) A. f e. ( H ` u ) ( g ( u .x. z ) f ) e. _V | 
						
							| 69 |  | mpo2eqb |  |-  ( A. g e. ( ( 2nd ` u ) H z ) A. f e. ( H ` u ) ( g ( u .x. z ) f ) e. _V -> ( ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) <-> A. g e. ( ( 2nd ` u ) H z ) A. f e. ( H ` u ) ( g ( u .x. z ) f ) = ( g ( u .xb z ) f ) ) ) | 
						
							| 70 | 68 69 | ax-mp |  |-  ( ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) <-> A. g e. ( ( 2nd ` u ) H z ) A. f e. ( H ` u ) ( g ( u .x. z ) f ) = ( g ( u .xb z ) f ) ) | 
						
							| 71 |  | ralcom |  |-  ( A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) <-> A. g e. ( y H z ) A. f e. ( x H y ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) | 
						
							| 72 | 66 70 71 | 3bitr4g |  |-  ( u = <. x , y >. -> ( ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) <-> A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) | 
						
							| 73 | 72 | ralbidv |  |-  ( u = <. x , y >. -> ( A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) <-> A. z e. B A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) | 
						
							| 74 | 73 | ralxp |  |-  ( A. u e. ( B X. B ) A. z e. B ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) = ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) <-> A. x e. B A. y e. B A. z e. B A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) | 
						
							| 75 | 52 74 | bitri |  |-  ( ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .x. z ) f ) ) ) = ( u e. ( B X. B ) , z e. B |-> ( g e. ( ( 2nd ` u ) H z ) , f e. ( H ` u ) |-> ( g ( u .xb z ) f ) ) ) <-> A. x e. B A. y e. B A. z e. B A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) | 
						
							| 76 | 46 75 | bitr3di |  |-  ( ph -> ( ( comf ` C ) = ( comf ` D ) <-> A. x e. B A. y e. B A. z e. B A. f e. ( x H y ) A. g e. ( y H z ) ( g ( <. x , y >. .x. z ) f ) = ( g ( <. x , y >. .xb z ) f ) ) ) |