| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mhmcoaddpsr.p |  |-  P = ( I mPwSer R ) | 
						
							| 2 |  | mhmcoaddpsr.q |  |-  Q = ( I mPwSer S ) | 
						
							| 3 |  | mhmcoaddpsr.b |  |-  B = ( Base ` P ) | 
						
							| 4 |  | mhmcoaddpsr.c |  |-  C = ( Base ` Q ) | 
						
							| 5 |  | mhmcoaddpsr.1 |  |-  .+ = ( +g ` P ) | 
						
							| 6 |  | mhmcoaddpsr.2 |  |-  .+b = ( +g ` Q ) | 
						
							| 7 |  | mhmcoaddpsr.h |  |-  ( ph -> H e. ( R MndHom S ) ) | 
						
							| 8 |  | mhmcoaddpsr.f |  |-  ( ph -> F e. B ) | 
						
							| 9 |  | mhmcoaddpsr.g |  |-  ( ph -> G e. B ) | 
						
							| 10 |  | fvexd |  |-  ( ph -> ( Base ` R ) e. _V ) | 
						
							| 11 |  | ovex |  |-  ( NN0 ^m I ) e. _V | 
						
							| 12 | 11 | rabex |  |-  { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } e. _V | 
						
							| 13 | 12 | a1i |  |-  ( ph -> { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } e. _V ) | 
						
							| 14 |  | eqid |  |-  ( Base ` R ) = ( Base ` R ) | 
						
							| 15 |  | eqid |  |-  { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } = { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } | 
						
							| 16 | 1 14 15 3 8 | psrelbas |  |-  ( ph -> F : { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } --> ( Base ` R ) ) | 
						
							| 17 | 10 13 16 | elmapdd |  |-  ( ph -> F e. ( ( Base ` R ) ^m { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } ) ) | 
						
							| 18 | 1 14 15 3 9 | psrelbas |  |-  ( ph -> G : { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } --> ( Base ` R ) ) | 
						
							| 19 | 10 13 18 | elmapdd |  |-  ( ph -> G e. ( ( Base ` R ) ^m { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } ) ) | 
						
							| 20 |  | eqid |  |-  ( +g ` R ) = ( +g ` R ) | 
						
							| 21 |  | eqid |  |-  ( +g ` S ) = ( +g ` S ) | 
						
							| 22 | 14 20 21 | mhmvlin |  |-  ( ( H e. ( R MndHom S ) /\ F e. ( ( Base ` R ) ^m { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } ) /\ G e. ( ( Base ` R ) ^m { f e. ( NN0 ^m I ) | ( `' f " NN ) e. Fin } ) ) -> ( H o. ( F oF ( +g ` R ) G ) ) = ( ( H o. F ) oF ( +g ` S ) ( H o. G ) ) ) | 
						
							| 23 | 7 17 19 22 | syl3anc |  |-  ( ph -> ( H o. ( F oF ( +g ` R ) G ) ) = ( ( H o. F ) oF ( +g ` S ) ( H o. G ) ) ) | 
						
							| 24 | 1 3 20 5 8 9 | psradd |  |-  ( ph -> ( F .+ G ) = ( F oF ( +g ` R ) G ) ) | 
						
							| 25 | 24 | coeq2d |  |-  ( ph -> ( H o. ( F .+ G ) ) = ( H o. ( F oF ( +g ` R ) G ) ) ) | 
						
							| 26 | 1 2 3 4 7 8 | mhmcopsr |  |-  ( ph -> ( H o. F ) e. C ) | 
						
							| 27 | 1 2 3 4 7 9 | mhmcopsr |  |-  ( ph -> ( H o. G ) e. C ) | 
						
							| 28 | 2 4 21 6 26 27 | psradd |  |-  ( ph -> ( ( H o. F ) .+b ( H o. G ) ) = ( ( H o. F ) oF ( +g ` S ) ( H o. G ) ) ) | 
						
							| 29 | 23 25 28 | 3eqtr4d |  |-  ( ph -> ( H o. ( F .+ G ) ) = ( ( H o. F ) .+b ( H o. G ) ) ) |