| Step | Hyp | Ref | Expression | 
						
							| 1 |  | rngchomrnghmresALTV.c |  |-  C = ( RngCatALTV ` U ) | 
						
							| 2 |  | rngchomrnghmresALTV.b |  |-  B = ( Rng i^i U ) | 
						
							| 3 |  | rngchomrnghmresALTV.u |  |-  ( ph -> U e. V ) | 
						
							| 4 |  | rngchomrnghmresALTV.f |  |-  F = ( Homf ` C ) | 
						
							| 5 |  | eqid |  |-  ( Base ` C ) = ( Base ` C ) | 
						
							| 6 | 1 5 3 | rngcbasALTV |  |-  ( ph -> ( Base ` C ) = ( U i^i Rng ) ) | 
						
							| 7 |  | inss2 |  |-  ( U i^i Rng ) C_ Rng | 
						
							| 8 | 6 7 | eqsstrdi |  |-  ( ph -> ( Base ` C ) C_ Rng ) | 
						
							| 9 |  | resmpo |  |-  ( ( ( Base ` C ) C_ Rng /\ ( Base ` C ) C_ Rng ) -> ( ( x e. Rng , y e. Rng |-> ( x RngHom y ) ) |` ( ( Base ` C ) X. ( Base ` C ) ) ) = ( x e. ( Base ` C ) , y e. ( Base ` C ) |-> ( x RngHom y ) ) ) | 
						
							| 10 | 8 8 9 | syl2anc |  |-  ( ph -> ( ( x e. Rng , y e. Rng |-> ( x RngHom y ) ) |` ( ( Base ` C ) X. ( Base ` C ) ) ) = ( x e. ( Base ` C ) , y e. ( Base ` C ) |-> ( x RngHom y ) ) ) | 
						
							| 11 |  | df-rnghm |  |-  RngHom = ( r e. Rng , s e. Rng |-> [_ ( Base ` r ) / v ]_ [_ ( Base ` s ) / w ]_ { f e. ( w ^m v ) | A. x e. v A. y e. v ( ( f ` ( x ( +g ` r ) y ) ) = ( ( f ` x ) ( +g ` s ) ( f ` y ) ) /\ ( f ` ( x ( .r ` r ) y ) ) = ( ( f ` x ) ( .r ` s ) ( f ` y ) ) ) } ) | 
						
							| 12 |  | ovex |  |-  ( w ^m v ) e. _V | 
						
							| 13 | 12 | rabex |  |-  { f e. ( w ^m v ) | A. x e. v A. y e. v ( ( f ` ( x ( +g ` r ) y ) ) = ( ( f ` x ) ( +g ` s ) ( f ` y ) ) /\ ( f ` ( x ( .r ` r ) y ) ) = ( ( f ` x ) ( .r ` s ) ( f ` y ) ) ) } e. _V | 
						
							| 14 | 13 | csbex |  |-  [_ ( Base ` s ) / w ]_ { f e. ( w ^m v ) | A. x e. v A. y e. v ( ( f ` ( x ( +g ` r ) y ) ) = ( ( f ` x ) ( +g ` s ) ( f ` y ) ) /\ ( f ` ( x ( .r ` r ) y ) ) = ( ( f ` x ) ( .r ` s ) ( f ` y ) ) ) } e. _V | 
						
							| 15 | 14 | csbex |  |-  [_ ( Base ` r ) / v ]_ [_ ( Base ` s ) / w ]_ { f e. ( w ^m v ) | A. x e. v A. y e. v ( ( f ` ( x ( +g ` r ) y ) ) = ( ( f ` x ) ( +g ` s ) ( f ` y ) ) /\ ( f ` ( x ( .r ` r ) y ) ) = ( ( f ` x ) ( .r ` s ) ( f ` y ) ) ) } e. _V | 
						
							| 16 | 11 15 | fnmpoi |  |-  RngHom Fn ( Rng X. Rng ) | 
						
							| 17 | 16 | a1i |  |-  ( ph -> RngHom Fn ( Rng X. Rng ) ) | 
						
							| 18 |  | fnov |  |-  ( RngHom Fn ( Rng X. Rng ) <-> RngHom = ( x e. Rng , y e. Rng |-> ( x RngHom y ) ) ) | 
						
							| 19 | 17 18 | sylib |  |-  ( ph -> RngHom = ( x e. Rng , y e. Rng |-> ( x RngHom y ) ) ) | 
						
							| 20 |  | incom |  |-  ( U i^i Rng ) = ( Rng i^i U ) | 
						
							| 21 | 20 | a1i |  |-  ( ph -> ( U i^i Rng ) = ( Rng i^i U ) ) | 
						
							| 22 | 2 | a1i |  |-  ( ph -> B = ( Rng i^i U ) ) | 
						
							| 23 | 21 6 22 | 3eqtr4rd |  |-  ( ph -> B = ( Base ` C ) ) | 
						
							| 24 | 23 | sqxpeqd |  |-  ( ph -> ( B X. B ) = ( ( Base ` C ) X. ( Base ` C ) ) ) | 
						
							| 25 | 19 24 | reseq12d |  |-  ( ph -> ( RngHom |` ( B X. B ) ) = ( ( x e. Rng , y e. Rng |-> ( x RngHom y ) ) |` ( ( Base ` C ) X. ( Base ` C ) ) ) ) | 
						
							| 26 | 1 5 3 4 | rngchomffvalALTV |  |-  ( ph -> F = ( x e. ( Base ` C ) , y e. ( Base ` C ) |-> ( x RngHom y ) ) ) | 
						
							| 27 | 10 25 26 | 3eqtr4rd |  |-  ( ph -> F = ( RngHom |` ( B X. B ) ) ) |