| Step | Hyp | Ref | Expression | 
						
							| 1 |  | evl1addd.q |  |-  O = ( eval1 ` R ) | 
						
							| 2 |  | evl1addd.p |  |-  P = ( Poly1 ` R ) | 
						
							| 3 |  | evl1addd.b |  |-  B = ( Base ` R ) | 
						
							| 4 |  | evl1addd.u |  |-  U = ( Base ` P ) | 
						
							| 5 |  | evl1addd.1 |  |-  ( ph -> R e. CRing ) | 
						
							| 6 |  | evl1addd.2 |  |-  ( ph -> Y e. B ) | 
						
							| 7 |  | evl1addd.3 |  |-  ( ph -> ( M e. U /\ ( ( O ` M ) ` Y ) = V ) ) | 
						
							| 8 |  | evl1addd.4 |  |-  ( ph -> ( N e. U /\ ( ( O ` N ) ` Y ) = W ) ) | 
						
							| 9 |  | evl1subd.s |  |-  .- = ( -g ` P ) | 
						
							| 10 |  | evl1subd.d |  |-  D = ( -g ` R ) | 
						
							| 11 |  | eqid |  |-  ( R ^s B ) = ( R ^s B ) | 
						
							| 12 | 1 2 11 3 | evl1rhm |  |-  ( R e. CRing -> O e. ( P RingHom ( R ^s B ) ) ) | 
						
							| 13 | 5 12 | syl |  |-  ( ph -> O e. ( P RingHom ( R ^s B ) ) ) | 
						
							| 14 |  | rhmghm |  |-  ( O e. ( P RingHom ( R ^s B ) ) -> O e. ( P GrpHom ( R ^s B ) ) ) | 
						
							| 15 | 13 14 | syl |  |-  ( ph -> O e. ( P GrpHom ( R ^s B ) ) ) | 
						
							| 16 |  | ghmgrp1 |  |-  ( O e. ( P GrpHom ( R ^s B ) ) -> P e. Grp ) | 
						
							| 17 | 15 16 | syl |  |-  ( ph -> P e. Grp ) | 
						
							| 18 | 7 | simpld |  |-  ( ph -> M e. U ) | 
						
							| 19 | 8 | simpld |  |-  ( ph -> N e. U ) | 
						
							| 20 | 4 9 | grpsubcl |  |-  ( ( P e. Grp /\ M e. U /\ N e. U ) -> ( M .- N ) e. U ) | 
						
							| 21 | 17 18 19 20 | syl3anc |  |-  ( ph -> ( M .- N ) e. U ) | 
						
							| 22 |  | eqid |  |-  ( -g ` ( R ^s B ) ) = ( -g ` ( R ^s B ) ) | 
						
							| 23 | 4 9 22 | ghmsub |  |-  ( ( O e. ( P GrpHom ( R ^s B ) ) /\ M e. U /\ N e. U ) -> ( O ` ( M .- N ) ) = ( ( O ` M ) ( -g ` ( R ^s B ) ) ( O ` N ) ) ) | 
						
							| 24 | 15 18 19 23 | syl3anc |  |-  ( ph -> ( O ` ( M .- N ) ) = ( ( O ` M ) ( -g ` ( R ^s B ) ) ( O ` N ) ) ) | 
						
							| 25 |  | crngring |  |-  ( R e. CRing -> R e. Ring ) | 
						
							| 26 |  | ringgrp |  |-  ( R e. Ring -> R e. Grp ) | 
						
							| 27 | 5 25 26 | 3syl |  |-  ( ph -> R e. Grp ) | 
						
							| 28 | 3 | fvexi |  |-  B e. _V | 
						
							| 29 | 28 | a1i |  |-  ( ph -> B e. _V ) | 
						
							| 30 |  | eqid |  |-  ( Base ` ( R ^s B ) ) = ( Base ` ( R ^s B ) ) | 
						
							| 31 | 4 30 | rhmf |  |-  ( O e. ( P RingHom ( R ^s B ) ) -> O : U --> ( Base ` ( R ^s B ) ) ) | 
						
							| 32 | 13 31 | syl |  |-  ( ph -> O : U --> ( Base ` ( R ^s B ) ) ) | 
						
							| 33 | 32 18 | ffvelcdmd |  |-  ( ph -> ( O ` M ) e. ( Base ` ( R ^s B ) ) ) | 
						
							| 34 | 32 19 | ffvelcdmd |  |-  ( ph -> ( O ` N ) e. ( Base ` ( R ^s B ) ) ) | 
						
							| 35 | 11 30 10 22 | pwssub |  |-  ( ( ( R e. Grp /\ B e. _V ) /\ ( ( O ` M ) e. ( Base ` ( R ^s B ) ) /\ ( O ` N ) e. ( Base ` ( R ^s B ) ) ) ) -> ( ( O ` M ) ( -g ` ( R ^s B ) ) ( O ` N ) ) = ( ( O ` M ) oF D ( O ` N ) ) ) | 
						
							| 36 | 27 29 33 34 35 | syl22anc |  |-  ( ph -> ( ( O ` M ) ( -g ` ( R ^s B ) ) ( O ` N ) ) = ( ( O ` M ) oF D ( O ` N ) ) ) | 
						
							| 37 | 24 36 | eqtrd |  |-  ( ph -> ( O ` ( M .- N ) ) = ( ( O ` M ) oF D ( O ` N ) ) ) | 
						
							| 38 | 37 | fveq1d |  |-  ( ph -> ( ( O ` ( M .- N ) ) ` Y ) = ( ( ( O ` M ) oF D ( O ` N ) ) ` Y ) ) | 
						
							| 39 | 11 3 30 5 29 33 | pwselbas |  |-  ( ph -> ( O ` M ) : B --> B ) | 
						
							| 40 | 39 | ffnd |  |-  ( ph -> ( O ` M ) Fn B ) | 
						
							| 41 | 11 3 30 5 29 34 | pwselbas |  |-  ( ph -> ( O ` N ) : B --> B ) | 
						
							| 42 | 41 | ffnd |  |-  ( ph -> ( O ` N ) Fn B ) | 
						
							| 43 |  | fnfvof |  |-  ( ( ( ( O ` M ) Fn B /\ ( O ` N ) Fn B ) /\ ( B e. _V /\ Y e. B ) ) -> ( ( ( O ` M ) oF D ( O ` N ) ) ` Y ) = ( ( ( O ` M ) ` Y ) D ( ( O ` N ) ` Y ) ) ) | 
						
							| 44 | 40 42 29 6 43 | syl22anc |  |-  ( ph -> ( ( ( O ` M ) oF D ( O ` N ) ) ` Y ) = ( ( ( O ` M ) ` Y ) D ( ( O ` N ) ` Y ) ) ) | 
						
							| 45 | 7 | simprd |  |-  ( ph -> ( ( O ` M ) ` Y ) = V ) | 
						
							| 46 | 8 | simprd |  |-  ( ph -> ( ( O ` N ) ` Y ) = W ) | 
						
							| 47 | 45 46 | oveq12d |  |-  ( ph -> ( ( ( O ` M ) ` Y ) D ( ( O ` N ) ` Y ) ) = ( V D W ) ) | 
						
							| 48 | 38 44 47 | 3eqtrd |  |-  ( ph -> ( ( O ` ( M .- N ) ) ` Y ) = ( V D W ) ) | 
						
							| 49 | 21 48 | jca |  |-  ( ph -> ( ( M .- N ) e. U /\ ( ( O ` ( M .- N ) ) ` Y ) = ( V D W ) ) ) |