| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ringsubdi.1 |  |-  G = ( 1st ` R ) | 
						
							| 2 |  | ringsubdi.2 |  |-  H = ( 2nd ` R ) | 
						
							| 3 |  | ringsubdi.3 |  |-  X = ran G | 
						
							| 4 |  | ringsubdi.4 |  |-  D = ( /g ` G ) | 
						
							| 5 |  | eqid |  |-  ( inv ` G ) = ( inv ` G ) | 
						
							| 6 | 1 3 5 4 | rngosub |  |-  ( ( R e. RingOps /\ A e. X /\ B e. X ) -> ( A D B ) = ( A G ( ( inv ` G ) ` B ) ) ) | 
						
							| 7 | 6 | 3adant3r3 |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( A D B ) = ( A G ( ( inv ` G ) ` B ) ) ) | 
						
							| 8 | 7 | oveq1d |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A D B ) H C ) = ( ( A G ( ( inv ` G ) ` B ) ) H C ) ) | 
						
							| 9 | 1 2 3 | rngocl |  |-  ( ( R e. RingOps /\ A e. X /\ C e. X ) -> ( A H C ) e. X ) | 
						
							| 10 | 9 | 3adant3r2 |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( A H C ) e. X ) | 
						
							| 11 | 1 2 3 | rngocl |  |-  ( ( R e. RingOps /\ B e. X /\ C e. X ) -> ( B H C ) e. X ) | 
						
							| 12 | 11 | 3adant3r1 |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( B H C ) e. X ) | 
						
							| 13 | 10 12 | jca |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A H C ) e. X /\ ( B H C ) e. X ) ) | 
						
							| 14 | 1 3 5 4 | rngosub |  |-  ( ( R e. RingOps /\ ( A H C ) e. X /\ ( B H C ) e. X ) -> ( ( A H C ) D ( B H C ) ) = ( ( A H C ) G ( ( inv ` G ) ` ( B H C ) ) ) ) | 
						
							| 15 | 14 | 3expb |  |-  ( ( R e. RingOps /\ ( ( A H C ) e. X /\ ( B H C ) e. X ) ) -> ( ( A H C ) D ( B H C ) ) = ( ( A H C ) G ( ( inv ` G ) ` ( B H C ) ) ) ) | 
						
							| 16 | 13 15 | syldan |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A H C ) D ( B H C ) ) = ( ( A H C ) G ( ( inv ` G ) ` ( B H C ) ) ) ) | 
						
							| 17 |  | idd |  |-  ( R e. RingOps -> ( A e. X -> A e. X ) ) | 
						
							| 18 | 1 3 5 | rngonegcl |  |-  ( ( R e. RingOps /\ B e. X ) -> ( ( inv ` G ) ` B ) e. X ) | 
						
							| 19 | 18 | ex |  |-  ( R e. RingOps -> ( B e. X -> ( ( inv ` G ) ` B ) e. X ) ) | 
						
							| 20 |  | idd |  |-  ( R e. RingOps -> ( C e. X -> C e. X ) ) | 
						
							| 21 | 17 19 20 | 3anim123d |  |-  ( R e. RingOps -> ( ( A e. X /\ B e. X /\ C e. X ) -> ( A e. X /\ ( ( inv ` G ) ` B ) e. X /\ C e. X ) ) ) | 
						
							| 22 | 21 | imp |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( A e. X /\ ( ( inv ` G ) ` B ) e. X /\ C e. X ) ) | 
						
							| 23 | 1 2 3 | rngodir |  |-  ( ( R e. RingOps /\ ( A e. X /\ ( ( inv ` G ) ` B ) e. X /\ C e. X ) ) -> ( ( A G ( ( inv ` G ) ` B ) ) H C ) = ( ( A H C ) G ( ( ( inv ` G ) ` B ) H C ) ) ) | 
						
							| 24 | 22 23 | syldan |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A G ( ( inv ` G ) ` B ) ) H C ) = ( ( A H C ) G ( ( ( inv ` G ) ` B ) H C ) ) ) | 
						
							| 25 | 1 2 3 5 | rngoneglmul |  |-  ( ( R e. RingOps /\ B e. X /\ C e. X ) -> ( ( inv ` G ) ` ( B H C ) ) = ( ( ( inv ` G ) ` B ) H C ) ) | 
						
							| 26 | 25 | 3adant3r1 |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( inv ` G ) ` ( B H C ) ) = ( ( ( inv ` G ) ` B ) H C ) ) | 
						
							| 27 | 26 | oveq2d |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A H C ) G ( ( inv ` G ) ` ( B H C ) ) ) = ( ( A H C ) G ( ( ( inv ` G ) ` B ) H C ) ) ) | 
						
							| 28 | 24 27 | eqtr4d |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A G ( ( inv ` G ) ` B ) ) H C ) = ( ( A H C ) G ( ( inv ` G ) ` ( B H C ) ) ) ) | 
						
							| 29 | 16 28 | eqtr4d |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A H C ) D ( B H C ) ) = ( ( A G ( ( inv ` G ) ` B ) ) H C ) ) | 
						
							| 30 | 8 29 | eqtr4d |  |-  ( ( R e. RingOps /\ ( A e. X /\ B e. X /\ C e. X ) ) -> ( ( A D B ) H C ) = ( ( A H C ) D ( B H C ) ) ) |