| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 0p1e1 |  |-  ( 0 + 1 ) = 1 | 
						
							| 2 | 1 | fveq2i |  |-  ( ( S Dn F ) ` ( 0 + 1 ) ) = ( ( S Dn F ) ` 1 ) | 
						
							| 3 |  | 0nn0 |  |-  0 e. NN0 | 
						
							| 4 |  | dvnp1 |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) /\ 0 e. NN0 ) -> ( ( S Dn F ) ` ( 0 + 1 ) ) = ( S _D ( ( S Dn F ) ` 0 ) ) ) | 
						
							| 5 | 3 4 | mp3an3 |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) ) -> ( ( S Dn F ) ` ( 0 + 1 ) ) = ( S _D ( ( S Dn F ) ` 0 ) ) ) | 
						
							| 6 |  | dvn0 |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) ) -> ( ( S Dn F ) ` 0 ) = F ) | 
						
							| 7 | 6 | oveq2d |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) ) -> ( S _D ( ( S Dn F ) ` 0 ) ) = ( S _D F ) ) | 
						
							| 8 | 5 7 | eqtrd |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) ) -> ( ( S Dn F ) ` ( 0 + 1 ) ) = ( S _D F ) ) | 
						
							| 9 | 2 8 | eqtr3id |  |-  ( ( S C_ CC /\ F e. ( CC ^pm S ) ) -> ( ( S Dn F ) ` 1 ) = ( S _D F ) ) |