| 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 | 1 2 3 4 5 6 7 8 9 | rngqiprnglinlem2 |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> [ ( A .x. C ) ] .~ = ( [ A ] .~ ( .r ` Q ) [ C ] .~ ) ) | 
						
							| 11 | 1 | anim1i |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( R e. Rng /\ ( A e. B /\ C e. B ) ) ) | 
						
							| 12 |  | 3anass |  |-  ( ( R e. Rng /\ A e. B /\ C e. B ) <-> ( R e. Rng /\ ( A e. B /\ C e. B ) ) ) | 
						
							| 13 | 11 12 | sylibr |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( R e. Rng /\ A e. B /\ C e. B ) ) | 
						
							| 14 | 5 6 | rngcl |  |-  ( ( R e. Rng /\ A e. B /\ C e. B ) -> ( A .x. C ) e. B ) | 
						
							| 15 | 13 14 | syl |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( A .x. C ) e. B ) | 
						
							| 16 |  | eqid |  |-  ( Base ` Q ) = ( Base ` Q ) | 
						
							| 17 | 8 9 5 16 | quseccl0 |  |-  ( ( R e. Rng /\ ( A .x. C ) e. B ) -> [ ( A .x. C ) ] .~ e. ( Base ` Q ) ) | 
						
							| 18 | 1 15 17 | syl2an2r |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> [ ( A .x. C ) ] .~ e. ( Base ` Q ) ) | 
						
							| 19 | 10 18 | eqeltrrd |  |-  ( ( ph /\ ( A e. B /\ C e. B ) ) -> ( [ A ] .~ ( .r ` Q ) [ C ] .~ ) e. ( Base ` Q ) ) |