| Step | Hyp | Ref | Expression | 
						
							| 1 |  | simp1 |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> N e. NN ) | 
						
							| 2 |  | simp2l |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> A e. ( EE ` N ) ) | 
						
							| 3 |  | simp2r |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> B e. ( EE ` N ) ) | 
						
							| 4 |  | simp3l |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> C e. ( EE ` N ) ) | 
						
							| 5 |  | simp3r |  |-  ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) -> D e. ( EE ` N ) ) | 
						
							| 6 |  | simpr |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ <. A , B >. Cgr <. C , D >. ) -> <. A , B >. Cgr <. C , D >. ) | 
						
							| 7 |  | simpl1 |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ <. A , B >. Cgr <. C , D >. ) -> N e. NN ) | 
						
							| 8 |  | simpl2l |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ <. A , B >. Cgr <. C , D >. ) -> A e. ( EE ` N ) ) | 
						
							| 9 |  | simpl2r |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ <. A , B >. Cgr <. C , D >. ) -> B e. ( EE ` N ) ) | 
						
							| 10 | 7 8 9 | cgrrflxd |  |-  ( ( ( N e. NN /\ ( A e. ( EE ` N ) /\ B e. ( EE ` N ) ) /\ ( C e. ( EE ` N ) /\ D e. ( EE ` N ) ) ) /\ <. A , B >. Cgr <. C , D >. ) -> <. A , B >. Cgr <. A , B >. ) | 
						
							| 11 | 1 2 3 4 5 2 3 6 10 | cgrtr4and |  |-  ( ( ( 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 >. ) | 
						
							| 12 | 11 | ex |  |-  ( ( 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 >. ) ) |