| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rng2idlring.r |  |-  ( ph -> R e. Rng ) | 
						
							| 2 |  | rng2idlring.i |  |-  ( ph -> I e. ( 2Ideal ` R ) ) | 
						
							| 3 |  | rng2idlring.j |  |-  J = ( R |`s I ) | 
						
							| 4 |  | rng2idlring.u |  |-  ( ph -> J e. Ring ) | 
						
							| 5 |  | rng2idlring.b |  |-  B = ( Base ` R ) | 
						
							| 6 |  | rng2idlring.t |  |-  .x. = ( .r ` R ) | 
						
							| 7 |  | rng2idlring.1 |  |-  .1. = ( 1r ` J ) | 
						
							| 8 |  | rngqiprngim.g |  |-  .~ = ( R ~QG I ) | 
						
							| 9 |  | rngqiprngim.q |  |-  Q = ( R /s .~ ) | 
						
							| 10 |  | ringrng |  |-  ( J e. Ring -> J e. Rng ) | 
						
							| 11 | 4 10 | syl |  |-  ( ph -> J e. Rng ) | 
						
							| 12 | 3 11 | eqeltrrid |  |-  ( ph -> ( R |`s I ) e. Rng ) | 
						
							| 13 | 1 2 12 | rng2idlsubrng |  |-  ( ph -> I e. ( SubRng ` R ) ) | 
						
							| 14 |  | subrngsubg |  |-  ( I e. ( SubRng ` R ) -> I e. ( SubGrp ` R ) ) | 
						
							| 15 | 13 14 | syl |  |-  ( ph -> I e. ( SubGrp ` R ) ) | 
						
							| 16 | 1 2 15 | 3jca |  |-  ( ph -> ( R e. Rng /\ I e. ( 2Ideal ` R ) /\ I e. ( SubGrp ` R ) ) ) | 
						
							| 17 |  | eqid |  |-  ( R ~QG I ) = ( R ~QG I ) | 
						
							| 18 | 8 | oveq2i |  |-  ( R /s .~ ) = ( R /s ( R ~QG I ) ) | 
						
							| 19 | 9 18 | eqtri |  |-  Q = ( R /s ( R ~QG I ) ) | 
						
							| 20 |  | eqid |  |-  ( .r ` Q ) = ( .r ` Q ) | 
						
							| 21 | 17 19 5 6 20 | qusmulrng |  |-  ( ( ( R e. Rng /\ I e. ( 2Ideal ` R ) /\ I e. ( SubGrp ` R ) ) /\ ( A e. B /\ C e. B ) ) -> ( [ A ] ( R ~QG I ) ( .r ` Q ) [ C ] ( R ~QG I ) ) = [ ( A .x. C ) ] ( R ~QG I ) ) | 
						
							| 22 | 16 21 | sylan |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( [ A ] ( R ~QG I ) ( .r ` Q ) [ C ] ( R ~QG I ) ) = [ ( A .x. C ) ] ( R ~QG I ) ) | 
						
							| 23 | 8 | eceq2i |  |-  [ A ] .~ = [ A ] ( R ~QG I ) | 
						
							| 24 | 8 | eceq2i |  |-  [ C ] .~ = [ C ] ( R ~QG I ) | 
						
							| 25 | 23 24 | oveq12i |  |-  ( [ A ] .~ ( .r ` Q ) [ C ] .~ ) = ( [ A ] ( R ~QG I ) ( .r ` Q ) [ C ] ( R ~QG I ) ) | 
						
							| 26 | 8 | eceq2i |  |-  [ ( A .x. C ) ] .~ = [ ( A .x. C ) ] ( R ~QG I ) | 
						
							| 27 | 22 25 26 | 3eqtr4g |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( [ A ] .~ ( .r ` Q ) [ C ] .~ ) = [ ( A .x. C ) ] .~ ) | 
						
							| 28 | 27 | eqcomd |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> [ ( A .x. C ) ] .~ = ( [ A ] .~ ( .r ` Q ) [ C ] .~ ) ) |