| Step | Hyp | Ref | Expression | 
						
							| 1 |  | prdsbasmpt.y |  |-  Y = ( S Xs_ R ) | 
						
							| 2 |  | prdsbasmpt.b |  |-  B = ( Base ` Y ) | 
						
							| 3 |  | prdsbasmpt.s |  |-  ( ph -> S e. V ) | 
						
							| 4 |  | prdsbasmpt.i |  |-  ( ph -> I e. W ) | 
						
							| 5 |  | prdsbasmpt.r |  |-  ( ph -> R Fn I ) | 
						
							| 6 | 1 2 3 4 5 | prdsbas2 |  |-  ( ph -> B = X_ x e. I ( Base ` ( R ` x ) ) ) | 
						
							| 7 | 6 | eleq2d |  |-  ( ph -> ( ( x e. I |-> U ) e. B <-> ( x e. I |-> U ) e. X_ x e. I ( Base ` ( R ` x ) ) ) ) | 
						
							| 8 |  | mptelixpg |  |-  ( I e. W -> ( ( x e. I |-> U ) e. X_ x e. I ( Base ` ( R ` x ) ) <-> A. x e. I U e. ( Base ` ( R ` x ) ) ) ) | 
						
							| 9 | 4 8 | syl |  |-  ( ph -> ( ( x e. I |-> U ) e. X_ x e. I ( Base ` ( R ` x ) ) <-> A. x e. I U e. ( Base ` ( R ` x ) ) ) ) | 
						
							| 10 | 7 9 | bitrd |  |-  ( ph -> ( ( x e. I |-> U ) e. B <-> A. x e. I U e. ( Base ` ( R ` x ) ) ) ) |