| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 6p5lem.1 |  | 
						
							| 2 |  | 6p5lem.2 |  | 
						
							| 3 |  | 6p5lem.3 |  | 
						
							| 4 |  | 6p5lem.4 |  | 
						
							| 5 |  | 6p5lem.5 |  | 
						
							| 6 |  | 6p5lem.6 | Could not format  ( A + D ) = ; 1 E : No typesetting found for |- ( A + D ) = ; 1 E with typecode |- | 
						
							| 7 | 4 | oveq2i |  | 
						
							| 8 | 1 | nn0cni |  | 
						
							| 9 | 2 | nn0cni |  | 
						
							| 10 |  | ax-1cn |  | 
						
							| 11 | 8 9 10 | addassi |  | 
						
							| 12 |  | 1nn0 |  | 
						
							| 13 | 5 | eqcomi |  | 
						
							| 14 | 12 3 13 6 | decsuc | Could not format  ( ( A + D ) + 1 ) = ; 1 C : No typesetting found for |- ( ( A + D ) + 1 ) = ; 1 C with typecode |- | 
						
							| 15 | 7 11 14 | 3eqtr2i | Could not format  ( A + B ) = ; 1 C : No typesetting found for |- ( A + B ) = ; 1 C with typecode |- |