| Step | Hyp | Ref | Expression | 
						
							| 1 |  | caovdir2d.1 |  |-  ( ( ph /\ ( x e. S /\ y e. S /\ z e. S ) ) -> ( x G ( y F z ) ) = ( ( x G y ) F ( x G z ) ) ) | 
						
							| 2 |  | caovdir2d.2 |  |-  ( ph -> A e. S ) | 
						
							| 3 |  | caovdir2d.3 |  |-  ( ph -> B e. S ) | 
						
							| 4 |  | caovdir2d.4 |  |-  ( ph -> C e. S ) | 
						
							| 5 |  | caovdir2d.cl |  |-  ( ( ph /\ ( x e. S /\ y e. S ) ) -> ( x F y ) e. S ) | 
						
							| 6 |  | caovdir2d.com |  |-  ( ( ph /\ ( x e. S /\ y e. S ) ) -> ( x G y ) = ( y G x ) ) | 
						
							| 7 | 1 4 2 3 | caovdid |  |-  ( ph -> ( C G ( A F B ) ) = ( ( C G A ) F ( C G B ) ) ) | 
						
							| 8 | 5 2 3 | caovcld |  |-  ( ph -> ( A F B ) e. S ) | 
						
							| 9 | 6 8 4 | caovcomd |  |-  ( ph -> ( ( A F B ) G C ) = ( C G ( A F B ) ) ) | 
						
							| 10 | 6 2 4 | caovcomd |  |-  ( ph -> ( A G C ) = ( C G A ) ) | 
						
							| 11 | 6 3 4 | caovcomd |  |-  ( ph -> ( B G C ) = ( C G B ) ) | 
						
							| 12 | 10 11 | oveq12d |  |-  ( ph -> ( ( A G C ) F ( B G C ) ) = ( ( C G A ) F ( C G B ) ) ) | 
						
							| 13 | 7 9 12 | 3eqtr4d |  |-  ( ph -> ( ( A F B ) G C ) = ( ( A G C ) F ( B G C ) ) ) |