| Step | Hyp | Ref | Expression | 
						
							| 1 |  | prdsinvgd2.y |  |-  Y = ( S Xs_ R ) | 
						
							| 2 |  | prdsinvgd2.i |  |-  ( ph -> I e. W ) | 
						
							| 3 |  | prdsinvgd2.s |  |-  ( ph -> S e. V ) | 
						
							| 4 |  | prdsinvgd2.r |  |-  ( ph -> R : I --> Grp ) | 
						
							| 5 |  | prdsinvgd2.b |  |-  B = ( Base ` Y ) | 
						
							| 6 |  | prdsinvgd2.n |  |-  N = ( invg ` Y ) | 
						
							| 7 |  | prdsinvgd2.x |  |-  ( ph -> X e. B ) | 
						
							| 8 |  | prdsinvgd2.j |  |-  ( ph -> J e. I ) | 
						
							| 9 | 1 2 3 4 5 6 7 | prdsinvgd |  |-  ( ph -> ( N ` X ) = ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) ) | 
						
							| 10 | 9 | fveq1d |  |-  ( ph -> ( ( N ` X ) ` J ) = ( ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) ` J ) ) | 
						
							| 11 |  | 2fveq3 |  |-  ( x = J -> ( invg ` ( R ` x ) ) = ( invg ` ( R ` J ) ) ) | 
						
							| 12 |  | fveq2 |  |-  ( x = J -> ( X ` x ) = ( X ` J ) ) | 
						
							| 13 | 11 12 | fveq12d |  |-  ( x = J -> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) = ( ( invg ` ( R ` J ) ) ` ( X ` J ) ) ) | 
						
							| 14 |  | eqid |  |-  ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) = ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) | 
						
							| 15 |  | fvex |  |-  ( ( invg ` ( R ` J ) ) ` ( X ` J ) ) e. _V | 
						
							| 16 | 13 14 15 | fvmpt |  |-  ( J e. I -> ( ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) ` J ) = ( ( invg ` ( R ` J ) ) ` ( X ` J ) ) ) | 
						
							| 17 | 8 16 | syl |  |-  ( ph -> ( ( x e. I |-> ( ( invg ` ( R ` x ) ) ` ( X ` x ) ) ) ` J ) = ( ( invg ` ( R ` J ) ) ` ( X ` J ) ) ) | 
						
							| 18 | 10 17 | eqtrd |  |-  ( ph -> ( ( N ` X ) ` J ) = ( ( invg ` ( R ` J ) ) ` ( X ` J ) ) ) |