| Step | Hyp | Ref | Expression | 
						
							| 1 |  | opprqus.b |  |-  B = ( Base ` R ) | 
						
							| 2 |  | opprqus.o |  |-  O = ( oppR ` R ) | 
						
							| 3 |  | opprqus.q |  |-  Q = ( R /s ( R ~QG I ) ) | 
						
							| 4 |  | opprqus.i |  |-  ( ph -> I e. ( NrmSGrp ` R ) ) | 
						
							| 5 |  | opprqusplusg.e |  |-  E = ( Base ` Q ) | 
						
							| 6 |  | opprqusplusg.x |  |-  ( ph -> X e. E ) | 
						
							| 7 |  | opprqusplusg.y |  |-  ( ph -> Y e. E ) | 
						
							| 8 |  | eqid |  |-  ( oppR ` Q ) = ( oppR ` Q ) | 
						
							| 9 |  | eqid |  |-  ( +g ` Q ) = ( +g ` Q ) | 
						
							| 10 | 8 9 | oppradd |  |-  ( +g ` Q ) = ( +g ` ( oppR ` Q ) ) | 
						
							| 11 | 10 | oveqi |  |-  ( X ( +g ` Q ) Y ) = ( X ( +g ` ( oppR ` Q ) ) Y ) | 
						
							| 12 | 4 | ad4antr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> I e. ( NrmSGrp ` R ) ) | 
						
							| 13 |  | simp-4r |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> p e. B ) | 
						
							| 14 |  | simplr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> q e. B ) | 
						
							| 15 |  | eqid |  |-  ( +g ` R ) = ( +g ` R ) | 
						
							| 16 | 3 1 15 9 | qusadd |  |-  ( ( I e. ( NrmSGrp ` R ) /\ p e. B /\ q e. B ) -> ( [ p ] ( R ~QG I ) ( +g ` Q ) [ q ] ( R ~QG I ) ) = [ ( p ( +g ` R ) q ) ] ( R ~QG I ) ) | 
						
							| 17 | 12 13 14 16 | syl3anc |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( [ p ] ( R ~QG I ) ( +g ` Q ) [ q ] ( R ~QG I ) ) = [ ( p ( +g ` R ) q ) ] ( R ~QG I ) ) | 
						
							| 18 |  | simpllr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> X = [ p ] ( R ~QG I ) ) | 
						
							| 19 |  | simpr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> Y = [ q ] ( R ~QG I ) ) | 
						
							| 20 | 18 19 | oveq12d |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( X ( +g ` Q ) Y ) = ( [ p ] ( R ~QG I ) ( +g ` Q ) [ q ] ( R ~QG I ) ) ) | 
						
							| 21 | 4 | elfvexd |  |-  ( ph -> R e. _V ) | 
						
							| 22 |  | nsgsubg |  |-  ( I e. ( NrmSGrp ` R ) -> I e. ( SubGrp ` R ) ) | 
						
							| 23 | 1 | subgss |  |-  ( I e. ( SubGrp ` R ) -> I C_ B ) | 
						
							| 24 | 4 22 23 | 3syl |  |-  ( ph -> I C_ B ) | 
						
							| 25 | 2 1 | oppreqg |  |-  ( ( R e. _V /\ I C_ B ) -> ( R ~QG I ) = ( O ~QG I ) ) | 
						
							| 26 | 21 24 25 | syl2anc |  |-  ( ph -> ( R ~QG I ) = ( O ~QG I ) ) | 
						
							| 27 | 26 | eceq2d |  |-  ( ph -> [ p ] ( R ~QG I ) = [ p ] ( O ~QG I ) ) | 
						
							| 28 | 26 | eceq2d |  |-  ( ph -> [ q ] ( R ~QG I ) = [ q ] ( O ~QG I ) ) | 
						
							| 29 | 27 28 | oveq12d |  |-  ( ph -> ( [ p ] ( R ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( R ~QG I ) ) = ( [ p ] ( O ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( O ~QG I ) ) ) | 
						
							| 30 | 29 | ad4antr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( [ p ] ( R ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( R ~QG I ) ) = ( [ p ] ( O ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( O ~QG I ) ) ) | 
						
							| 31 | 2 | opprnsg |  |-  ( NrmSGrp ` R ) = ( NrmSGrp ` O ) | 
						
							| 32 | 4 31 | eleqtrdi |  |-  ( ph -> I e. ( NrmSGrp ` O ) ) | 
						
							| 33 | 32 | ad4antr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> I e. ( NrmSGrp ` O ) ) | 
						
							| 34 | 13 1 | eleqtrdi |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> p e. ( Base ` R ) ) | 
						
							| 35 | 14 1 | eleqtrdi |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> q e. ( Base ` R ) ) | 
						
							| 36 |  | eqid |  |-  ( O /s ( O ~QG I ) ) = ( O /s ( O ~QG I ) ) | 
						
							| 37 | 2 1 | opprbas |  |-  B = ( Base ` O ) | 
						
							| 38 | 1 37 | eqtr3i |  |-  ( Base ` R ) = ( Base ` O ) | 
						
							| 39 | 2 15 | oppradd |  |-  ( +g ` R ) = ( +g ` O ) | 
						
							| 40 |  | eqid |  |-  ( +g ` ( O /s ( O ~QG I ) ) ) = ( +g ` ( O /s ( O ~QG I ) ) ) | 
						
							| 41 | 36 38 39 40 | qusadd |  |-  ( ( I e. ( NrmSGrp ` O ) /\ p e. ( Base ` R ) /\ q e. ( Base ` R ) ) -> ( [ p ] ( O ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( O ~QG I ) ) = [ ( p ( +g ` R ) q ) ] ( O ~QG I ) ) | 
						
							| 42 | 33 34 35 41 | syl3anc |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( [ p ] ( O ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( O ~QG I ) ) = [ ( p ( +g ` R ) q ) ] ( O ~QG I ) ) | 
						
							| 43 | 30 42 | eqtrd |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( [ p ] ( R ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( R ~QG I ) ) = [ ( p ( +g ` R ) q ) ] ( O ~QG I ) ) | 
						
							| 44 | 18 19 | oveq12d |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) = ( [ p ] ( R ~QG I ) ( +g ` ( O /s ( O ~QG I ) ) ) [ q ] ( R ~QG I ) ) ) | 
						
							| 45 | 26 | ad4antr |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( R ~QG I ) = ( O ~QG I ) ) | 
						
							| 46 | 45 | eceq2d |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> [ ( p ( +g ` R ) q ) ] ( R ~QG I ) = [ ( p ( +g ` R ) q ) ] ( O ~QG I ) ) | 
						
							| 47 | 43 44 46 | 3eqtr4d |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) = [ ( p ( +g ` R ) q ) ] ( R ~QG I ) ) | 
						
							| 48 | 17 20 47 | 3eqtr4d |  |-  ( ( ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) /\ q e. B ) /\ Y = [ q ] ( R ~QG I ) ) -> ( X ( +g ` Q ) Y ) = ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) ) | 
						
							| 49 | 3 | a1i |  |-  ( ph -> Q = ( R /s ( R ~QG I ) ) ) | 
						
							| 50 | 1 | a1i |  |-  ( ph -> B = ( Base ` R ) ) | 
						
							| 51 |  | ovexd |  |-  ( ph -> ( R ~QG I ) e. _V ) | 
						
							| 52 | 49 50 51 21 | qusbas |  |-  ( ph -> ( B /. ( R ~QG I ) ) = ( Base ` Q ) ) | 
						
							| 53 | 5 52 | eqtr4id |  |-  ( ph -> E = ( B /. ( R ~QG I ) ) ) | 
						
							| 54 | 7 53 | eleqtrd |  |-  ( ph -> Y e. ( B /. ( R ~QG I ) ) ) | 
						
							| 55 | 54 | ad2antrr |  |-  ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) -> Y e. ( B /. ( R ~QG I ) ) ) | 
						
							| 56 |  | elqsi |  |-  ( Y e. ( B /. ( R ~QG I ) ) -> E. q e. B Y = [ q ] ( R ~QG I ) ) | 
						
							| 57 | 55 56 | syl |  |-  ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) -> E. q e. B Y = [ q ] ( R ~QG I ) ) | 
						
							| 58 | 48 57 | r19.29a |  |-  ( ( ( ph /\ p e. B ) /\ X = [ p ] ( R ~QG I ) ) -> ( X ( +g ` Q ) Y ) = ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) ) | 
						
							| 59 | 6 53 | eleqtrd |  |-  ( ph -> X e. ( B /. ( R ~QG I ) ) ) | 
						
							| 60 |  | elqsi |  |-  ( X e. ( B /. ( R ~QG I ) ) -> E. p e. B X = [ p ] ( R ~QG I ) ) | 
						
							| 61 | 59 60 | syl |  |-  ( ph -> E. p e. B X = [ p ] ( R ~QG I ) ) | 
						
							| 62 | 58 61 | r19.29a |  |-  ( ph -> ( X ( +g ` Q ) Y ) = ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) ) | 
						
							| 63 | 11 62 | eqtr3id |  |-  ( ph -> ( X ( +g ` ( oppR ` Q ) ) Y ) = ( X ( +g ` ( O /s ( O ~QG I ) ) ) Y ) ) |