| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rngcrescrhmALTV.u |  |-  ( ph -> U e. V ) | 
						
							| 2 |  | rngcrescrhmALTV.c |  |-  C = ( RngCatALTV ` U ) | 
						
							| 3 |  | rngcrescrhmALTV.r |  |-  ( ph -> R = ( Ring i^i U ) ) | 
						
							| 4 |  | rngcrescrhmALTV.h |  |-  H = ( RingHom |` ( R X. R ) ) | 
						
							| 5 |  | eqid |  |-  ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) = ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) | 
						
							| 6 |  | ovex |  |-  ( x GrpHom y ) e. _V | 
						
							| 7 | 6 | inex1 |  |-  ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) e. _V | 
						
							| 8 | 5 7 | fnmpoi |  |-  ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) Fn ( R X. R ) | 
						
							| 9 | 4 | a1i |  |-  ( ph -> H = ( RingHom |` ( R X. R ) ) ) | 
						
							| 10 |  | dfrhm2 |  |-  RingHom = ( x e. Ring , y e. Ring |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) | 
						
							| 11 | 10 | a1i |  |-  ( ph -> RingHom = ( x e. Ring , y e. Ring |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) ) | 
						
							| 12 | 11 | reseq1d |  |-  ( ph -> ( RingHom |` ( R X. R ) ) = ( ( x e. Ring , y e. Ring |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) |` ( R X. R ) ) ) | 
						
							| 13 |  | inss1 |  |-  ( Ring i^i U ) C_ Ring | 
						
							| 14 | 3 13 | eqsstrdi |  |-  ( ph -> R C_ Ring ) | 
						
							| 15 |  | resmpo |  |-  ( ( R C_ Ring /\ R C_ Ring ) -> ( ( x e. Ring , y e. Ring |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) |` ( R X. R ) ) = ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) ) | 
						
							| 16 | 14 14 15 | syl2anc |  |-  ( ph -> ( ( x e. Ring , y e. Ring |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) |` ( R X. R ) ) = ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) ) | 
						
							| 17 | 9 12 16 | 3eqtrd |  |-  ( ph -> H = ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) ) | 
						
							| 18 | 17 | fneq1d |  |-  ( ph -> ( H Fn ( R X. R ) <-> ( x e. R , y e. R |-> ( ( x GrpHom y ) i^i ( ( mulGrp ` x ) MndHom ( mulGrp ` y ) ) ) ) Fn ( R X. R ) ) ) | 
						
							| 19 | 8 18 | mpbiri |  |-  ( ph -> H Fn ( R X. R ) ) |