| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 1p1e2s | Could not format  ( 1s +s 1s ) = 2s : No typesetting found for |- ( 1s +s 1s ) = 2s with typecode |- | 
						
							| 2 | 1 | oveq1i | Could not format  ( ( 1s +s 1s ) x.s A ) = ( 2s x.s A ) : No typesetting found for |- ( ( 1s +s 1s ) x.s A ) = ( 2s x.s A ) with typecode |- | 
						
							| 3 | 2 | eqcomi | Could not format  ( 2s x.s A ) = ( ( 1s +s 1s ) x.s A ) : No typesetting found for |- ( 2s x.s A ) = ( ( 1s +s 1s ) x.s A ) with typecode |- | 
						
							| 4 |  | 1sno |  | 
						
							| 5 | 4 | a1i |  | 
						
							| 6 |  | id |  | 
						
							| 7 | 5 5 6 | addsdird |  | 
						
							| 8 |  | mulslid |  | 
						
							| 9 | 8 8 | oveq12d |  | 
						
							| 10 | 7 9 | eqtrd |  | 
						
							| 11 | 3 10 | eqtrid | Could not format  ( A e. No -> ( 2s x.s A ) = ( A +s A ) ) : No typesetting found for |- ( A e. No -> ( 2s x.s A ) = ( A +s A ) ) with typecode |- |