| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mdetfval.d |  |-  D = ( N maDet R ) | 
						
							| 2 |  | mdetfval.a |  |-  A = ( N Mat R ) | 
						
							| 3 |  | mdetfval.b |  |-  B = ( Base ` A ) | 
						
							| 4 |  | mdetfval.p |  |-  P = ( Base ` ( SymGrp ` N ) ) | 
						
							| 5 |  | mdetfval.y |  |-  Y = ( ZRHom ` R ) | 
						
							| 6 |  | mdetfval.s |  |-  S = ( pmSgn ` N ) | 
						
							| 7 |  | mdetfval.t |  |-  .x. = ( .r ` R ) | 
						
							| 8 |  | mdetfval.u |  |-  U = ( mulGrp ` R ) | 
						
							| 9 |  | oveq12 |  |-  ( ( n = N /\ r = R ) -> ( n Mat r ) = ( N Mat R ) ) | 
						
							| 10 | 9 2 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( n Mat r ) = A ) | 
						
							| 11 | 10 | fveq2d |  |-  ( ( n = N /\ r = R ) -> ( Base ` ( n Mat r ) ) = ( Base ` A ) ) | 
						
							| 12 | 11 3 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( Base ` ( n Mat r ) ) = B ) | 
						
							| 13 |  | simpr |  |-  ( ( n = N /\ r = R ) -> r = R ) | 
						
							| 14 |  | simpl |  |-  ( ( n = N /\ r = R ) -> n = N ) | 
						
							| 15 | 14 | fveq2d |  |-  ( ( n = N /\ r = R ) -> ( SymGrp ` n ) = ( SymGrp ` N ) ) | 
						
							| 16 | 15 | fveq2d |  |-  ( ( n = N /\ r = R ) -> ( Base ` ( SymGrp ` n ) ) = ( Base ` ( SymGrp ` N ) ) ) | 
						
							| 17 | 16 4 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( Base ` ( SymGrp ` n ) ) = P ) | 
						
							| 18 |  | fveq2 |  |-  ( r = R -> ( .r ` r ) = ( .r ` R ) ) | 
						
							| 19 | 18 | adantl |  |-  ( ( n = N /\ r = R ) -> ( .r ` r ) = ( .r ` R ) ) | 
						
							| 20 | 19 7 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( .r ` r ) = .x. ) | 
						
							| 21 | 13 | fveq2d |  |-  ( ( n = N /\ r = R ) -> ( ZRHom ` r ) = ( ZRHom ` R ) ) | 
						
							| 22 | 21 5 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( ZRHom ` r ) = Y ) | 
						
							| 23 |  | fveq2 |  |-  ( n = N -> ( pmSgn ` n ) = ( pmSgn ` N ) ) | 
						
							| 24 | 23 | adantr |  |-  ( ( n = N /\ r = R ) -> ( pmSgn ` n ) = ( pmSgn ` N ) ) | 
						
							| 25 | 24 6 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( pmSgn ` n ) = S ) | 
						
							| 26 | 22 25 | coeq12d |  |-  ( ( n = N /\ r = R ) -> ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) = ( Y o. S ) ) | 
						
							| 27 | 26 | fveq1d |  |-  ( ( n = N /\ r = R ) -> ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) = ( ( Y o. S ) ` p ) ) | 
						
							| 28 |  | fveq2 |  |-  ( r = R -> ( mulGrp ` r ) = ( mulGrp ` R ) ) | 
						
							| 29 | 28 | adantl |  |-  ( ( n = N /\ r = R ) -> ( mulGrp ` r ) = ( mulGrp ` R ) ) | 
						
							| 30 | 29 8 | eqtr4di |  |-  ( ( n = N /\ r = R ) -> ( mulGrp ` r ) = U ) | 
						
							| 31 | 14 | mpteq1d |  |-  ( ( n = N /\ r = R ) -> ( x e. n |-> ( ( p ` x ) m x ) ) = ( x e. N |-> ( ( p ` x ) m x ) ) ) | 
						
							| 32 | 30 31 | oveq12d |  |-  ( ( n = N /\ r = R ) -> ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) = ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) | 
						
							| 33 | 20 27 32 | oveq123d |  |-  ( ( n = N /\ r = R ) -> ( ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) ( .r ` r ) ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) ) = ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) | 
						
							| 34 | 17 33 | mpteq12dv |  |-  ( ( n = N /\ r = R ) -> ( p e. ( Base ` ( SymGrp ` n ) ) |-> ( ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) ( .r ` r ) ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) ) ) = ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) | 
						
							| 35 | 13 34 | oveq12d |  |-  ( ( n = N /\ r = R ) -> ( r gsum ( p e. ( Base ` ( SymGrp ` n ) ) |-> ( ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) ( .r ` r ) ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) ) ) ) = ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) | 
						
							| 36 | 12 35 | mpteq12dv |  |-  ( ( n = N /\ r = R ) -> ( m e. ( Base ` ( n Mat r ) ) |-> ( r gsum ( p e. ( Base ` ( SymGrp ` n ) ) |-> ( ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) ( .r ` r ) ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) ) ) ) ) = ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 37 |  | df-mdet |  |-  maDet = ( n e. _V , r e. _V |-> ( m e. ( Base ` ( n Mat r ) ) |-> ( r gsum ( p e. ( Base ` ( SymGrp ` n ) ) |-> ( ( ( ( ZRHom ` r ) o. ( pmSgn ` n ) ) ` p ) ( .r ` r ) ( ( mulGrp ` r ) gsum ( x e. n |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 38 | 3 | fvexi |  |-  B e. _V | 
						
							| 39 | 38 | mptex |  |-  ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) e. _V | 
						
							| 40 | 36 37 39 | ovmpoa |  |-  ( ( N e. _V /\ R e. _V ) -> ( N maDet R ) = ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 41 | 37 | reldmmpo |  |-  Rel dom maDet | 
						
							| 42 | 41 | ovprc |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( N maDet R ) = (/) ) | 
						
							| 43 |  | mpt0 |  |-  ( m e. (/) |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) = (/) | 
						
							| 44 | 42 43 | eqtr4di |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( N maDet R ) = ( m e. (/) |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 45 |  | df-mat |  |-  Mat = ( y e. Fin , z e. _V |-> ( ( z freeLMod ( y X. y ) ) sSet <. ( .r ` ndx ) , ( z maMul <. y , y , y >. ) >. ) ) | 
						
							| 46 | 45 | reldmmpo |  |-  Rel dom Mat | 
						
							| 47 | 46 | ovprc |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( N Mat R ) = (/) ) | 
						
							| 48 | 2 47 | eqtrid |  |-  ( -. ( N e. _V /\ R e. _V ) -> A = (/) ) | 
						
							| 49 | 48 | fveq2d |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( Base ` A ) = ( Base ` (/) ) ) | 
						
							| 50 |  | base0 |  |-  (/) = ( Base ` (/) ) | 
						
							| 51 | 49 3 50 | 3eqtr4g |  |-  ( -. ( N e. _V /\ R e. _V ) -> B = (/) ) | 
						
							| 52 | 51 | mpteq1d |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) = ( m e. (/) |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 53 | 44 52 | eqtr4d |  |-  ( -. ( N e. _V /\ R e. _V ) -> ( N maDet R ) = ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) ) | 
						
							| 54 | 40 53 | pm2.61i |  |-  ( N maDet R ) = ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) | 
						
							| 55 | 1 54 | eqtri |  |-  D = ( m e. B |-> ( R gsum ( p e. P |-> ( ( ( Y o. S ) ` p ) .x. ( U gsum ( x e. N |-> ( ( p ` x ) m x ) ) ) ) ) ) ) |