| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-decpmat |  |-  decompPMat = ( m e. _V , k e. NN0 |-> ( i e. dom dom m , j e. dom dom m |-> ( ( coe1 ` ( i m j ) ) ` k ) ) ) | 
						
							| 2 | 1 | a1i |  |-  ( ( M e. V /\ K e. NN0 ) -> decompPMat = ( m e. _V , k e. NN0 |-> ( i e. dom dom m , j e. dom dom m |-> ( ( coe1 ` ( i m j ) ) ` k ) ) ) ) | 
						
							| 3 |  | dmeq |  |-  ( m = M -> dom m = dom M ) | 
						
							| 4 | 3 | adantr |  |-  ( ( m = M /\ k = K ) -> dom m = dom M ) | 
						
							| 5 | 4 | dmeqd |  |-  ( ( m = M /\ k = K ) -> dom dom m = dom dom M ) | 
						
							| 6 |  | oveq |  |-  ( m = M -> ( i m j ) = ( i M j ) ) | 
						
							| 7 | 6 | fveq2d |  |-  ( m = M -> ( coe1 ` ( i m j ) ) = ( coe1 ` ( i M j ) ) ) | 
						
							| 8 | 7 | adantr |  |-  ( ( m = M /\ k = K ) -> ( coe1 ` ( i m j ) ) = ( coe1 ` ( i M j ) ) ) | 
						
							| 9 |  | simpr |  |-  ( ( m = M /\ k = K ) -> k = K ) | 
						
							| 10 | 8 9 | fveq12d |  |-  ( ( m = M /\ k = K ) -> ( ( coe1 ` ( i m j ) ) ` k ) = ( ( coe1 ` ( i M j ) ) ` K ) ) | 
						
							| 11 | 5 5 10 | mpoeq123dv |  |-  ( ( m = M /\ k = K ) -> ( i e. dom dom m , j e. dom dom m |-> ( ( coe1 ` ( i m j ) ) ` k ) ) = ( i e. dom dom M , j e. dom dom M |-> ( ( coe1 ` ( i M j ) ) ` K ) ) ) | 
						
							| 12 | 11 | adantl |  |-  ( ( ( M e. V /\ K e. NN0 ) /\ ( m = M /\ k = K ) ) -> ( i e. dom dom m , j e. dom dom m |-> ( ( coe1 ` ( i m j ) ) ` k ) ) = ( i e. dom dom M , j e. dom dom M |-> ( ( coe1 ` ( i M j ) ) ` K ) ) ) | 
						
							| 13 |  | elex |  |-  ( M e. V -> M e. _V ) | 
						
							| 14 | 13 | adantr |  |-  ( ( M e. V /\ K e. NN0 ) -> M e. _V ) | 
						
							| 15 |  | simpr |  |-  ( ( M e. V /\ K e. NN0 ) -> K e. NN0 ) | 
						
							| 16 |  | dmexg |  |-  ( M e. V -> dom M e. _V ) | 
						
							| 17 | 16 | dmexd |  |-  ( M e. V -> dom dom M e. _V ) | 
						
							| 18 | 17 17 | jca |  |-  ( M e. V -> ( dom dom M e. _V /\ dom dom M e. _V ) ) | 
						
							| 19 | 18 | adantr |  |-  ( ( M e. V /\ K e. NN0 ) -> ( dom dom M e. _V /\ dom dom M e. _V ) ) | 
						
							| 20 |  | mpoexga |  |-  ( ( dom dom M e. _V /\ dom dom M e. _V ) -> ( i e. dom dom M , j e. dom dom M |-> ( ( coe1 ` ( i M j ) ) ` K ) ) e. _V ) | 
						
							| 21 | 19 20 | syl |  |-  ( ( M e. V /\ K e. NN0 ) -> ( i e. dom dom M , j e. dom dom M |-> ( ( coe1 ` ( i M j ) ) ` K ) ) e. _V ) | 
						
							| 22 | 2 12 14 15 21 | ovmpod |  |-  ( ( M e. V /\ K e. NN0 ) -> ( M decompPMat K ) = ( i e. dom dom M , j e. dom dom M |-> ( ( coe1 ` ( i M j ) ) ` K ) ) ) |