| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eulerpartlems.r |  |-  R = { f | ( `' f " NN ) e. Fin } | 
						
							| 2 |  | eulerpartlems.s |  |-  S = ( f e. ( ( NN0 ^m NN ) i^i R ) |-> sum_ k e. NN ( ( f ` k ) x. k ) ) | 
						
							| 3 |  | simpl |  |-  ( ( g = f /\ k e. NN ) -> g = f ) | 
						
							| 4 | 3 | fveq1d |  |-  ( ( g = f /\ k e. NN ) -> ( g ` k ) = ( f ` k ) ) | 
						
							| 5 | 4 | oveq1d |  |-  ( ( g = f /\ k e. NN ) -> ( ( g ` k ) x. k ) = ( ( f ` k ) x. k ) ) | 
						
							| 6 | 5 | sumeq2dv |  |-  ( g = f -> sum_ k e. NN ( ( g ` k ) x. k ) = sum_ k e. NN ( ( f ` k ) x. k ) ) | 
						
							| 7 | 6 | eleq1d |  |-  ( g = f -> ( sum_ k e. NN ( ( g ` k ) x. k ) e. NN0 <-> sum_ k e. NN ( ( f ` k ) x. k ) e. NN0 ) ) | 
						
							| 8 | 1 2 | eulerpartlemsv2 |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> ( S ` g ) = sum_ k e. ( `' g " NN ) ( ( g ` k ) x. k ) ) | 
						
							| 9 | 1 2 | eulerpartlemsv1 |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> ( S ` g ) = sum_ k e. NN ( ( g ` k ) x. k ) ) | 
						
							| 10 | 8 9 | eqtr3d |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> sum_ k e. ( `' g " NN ) ( ( g ` k ) x. k ) = sum_ k e. NN ( ( g ` k ) x. k ) ) | 
						
							| 11 | 1 2 | eulerpartlemelr |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> ( g : NN --> NN0 /\ ( `' g " NN ) e. Fin ) ) | 
						
							| 12 | 11 | simprd |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> ( `' g " NN ) e. Fin ) | 
						
							| 13 | 11 | simpld |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> g : NN --> NN0 ) | 
						
							| 14 | 13 | adantr |  |-  ( ( g e. ( ( NN0 ^m NN ) i^i R ) /\ k e. ( `' g " NN ) ) -> g : NN --> NN0 ) | 
						
							| 15 |  | cnvimass |  |-  ( `' g " NN ) C_ dom g | 
						
							| 16 | 15 13 | fssdm |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> ( `' g " NN ) C_ NN ) | 
						
							| 17 | 16 | sselda |  |-  ( ( g e. ( ( NN0 ^m NN ) i^i R ) /\ k e. ( `' g " NN ) ) -> k e. NN ) | 
						
							| 18 | 14 17 | ffvelcdmd |  |-  ( ( g e. ( ( NN0 ^m NN ) i^i R ) /\ k e. ( `' g " NN ) ) -> ( g ` k ) e. NN0 ) | 
						
							| 19 | 17 | nnnn0d |  |-  ( ( g e. ( ( NN0 ^m NN ) i^i R ) /\ k e. ( `' g " NN ) ) -> k e. NN0 ) | 
						
							| 20 | 18 19 | nn0mulcld |  |-  ( ( g e. ( ( NN0 ^m NN ) i^i R ) /\ k e. ( `' g " NN ) ) -> ( ( g ` k ) x. k ) e. NN0 ) | 
						
							| 21 | 12 20 | fsumnn0cl |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> sum_ k e. ( `' g " NN ) ( ( g ` k ) x. k ) e. NN0 ) | 
						
							| 22 | 10 21 | eqeltrrd |  |-  ( g e. ( ( NN0 ^m NN ) i^i R ) -> sum_ k e. NN ( ( g ` k ) x. k ) e. NN0 ) | 
						
							| 23 | 7 22 | vtoclga |  |-  ( f e. ( ( NN0 ^m NN ) i^i R ) -> sum_ k e. NN ( ( f ` k ) x. k ) e. NN0 ) | 
						
							| 24 | 2 23 | fmpti |  |-  S : ( ( NN0 ^m NN ) i^i R ) --> NN0 |