| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cgrcomand.1 |  |-  ( ph -> N e. NN ) | 
						
							| 2 |  | cgrcomand.2 |  |-  ( ph -> A e. ( EE ` N ) ) | 
						
							| 3 |  | cgrcomand.3 |  |-  ( ph -> B e. ( EE ` N ) ) | 
						
							| 4 |  | cgrcomand.4 |  |-  ( ph -> C e. ( EE ` N ) ) | 
						
							| 5 |  | cgrcomand.5 |  |-  ( ph -> D e. ( EE ` N ) ) | 
						
							| 6 |  | cgrcomand.6 |  |-  ( ( ph /\ ps ) -> <. A , B >. Cgr <. C , D >. ) | 
						
							| 7 |  | cgrcom |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> ( <. A , B >. Cgr <. C , D >. <-> <. C , D >. Cgr <. A , B >. ) ) | 
						
							| 8 | 1 2 3 4 5 7 | syl122anc |  |-  ( ph -> ( <. A , B >. Cgr <. C , D >. <-> <. C , D >. Cgr <. A , B >. ) ) | 
						
							| 9 | 8 | adantr |  |-  ( ( ph /\ ps ) -> ( <. A , B >. Cgr <. C , D >. <-> <. C , D >. Cgr <. A , B >. ) ) | 
						
							| 10 | 6 9 | mpbid |  |-  ( ( ph /\ ps ) -> <. C , D >. Cgr <. A , B >. ) |