| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 3factsumint3.1 |  |-  A = ( L [,] U ) | 
						
							| 2 |  | 3factsumint3.2 |  |-  ( ph -> L e. RR ) | 
						
							| 3 |  | 3factsumint3.3 |  |-  ( ph -> U e. RR ) | 
						
							| 4 |  | 3factsumint3.4 |  |-  ( ( ph /\ x e. A ) -> F e. CC ) | 
						
							| 5 |  | 3factsumint3.5 |  |-  ( ph -> ( x e. A |-> F ) e. ( A -cn-> CC ) ) | 
						
							| 6 |  | 3factsumint3.6 |  |-  ( ( ph /\ k e. B ) -> G e. CC ) | 
						
							| 7 |  | 3factsumint3.7 |  |-  ( ( ph /\ ( x e. A /\ k e. B ) ) -> H e. CC ) | 
						
							| 8 |  | 3factsumint3.8 |  |-  ( ( ph /\ k e. B ) -> ( x e. A |-> H ) e. ( A -cn-> CC ) ) | 
						
							| 9 | 4 | adantlr |  |-  ( ( ( ph /\ k e. B ) /\ x e. A ) -> F e. CC ) | 
						
							| 10 |  | ancom |  |-  ( ( x e. A /\ k e. B ) <-> ( k e. B /\ x e. A ) ) | 
						
							| 11 | 10 | anbi2i |  |-  ( ( ph /\ ( x e. A /\ k e. B ) ) <-> ( ph /\ ( k e. B /\ x e. A ) ) ) | 
						
							| 12 |  | anass |  |-  ( ( ( ph /\ k e. B ) /\ x e. A ) <-> ( ph /\ ( k e. B /\ x e. A ) ) ) | 
						
							| 13 | 12 | bicomi |  |-  ( ( ph /\ ( k e. B /\ x e. A ) ) <-> ( ( ph /\ k e. B ) /\ x e. A ) ) | 
						
							| 14 | 11 13 | bitri |  |-  ( ( ph /\ ( x e. A /\ k e. B ) ) <-> ( ( ph /\ k e. B ) /\ x e. A ) ) | 
						
							| 15 | 14 | imbi1i |  |-  ( ( ( ph /\ ( x e. A /\ k e. B ) ) -> H e. CC ) <-> ( ( ( ph /\ k e. B ) /\ x e. A ) -> H e. CC ) ) | 
						
							| 16 | 7 15 | mpbi |  |-  ( ( ( ph /\ k e. B ) /\ x e. A ) -> H e. CC ) | 
						
							| 17 | 9 16 | mulcld |  |-  ( ( ( ph /\ k e. B ) /\ x e. A ) -> ( F x. H ) e. CC ) | 
						
							| 18 | 2 | adantr |  |-  ( ( ph /\ k e. B ) -> L e. RR ) | 
						
							| 19 | 3 | adantr |  |-  ( ( ph /\ k e. B ) -> U e. RR ) | 
						
							| 20 | 5 | adantr |  |-  ( ( ph /\ k e. B ) -> ( x e. A |-> F ) e. ( A -cn-> CC ) ) | 
						
							| 21 | 20 8 | mulcncf |  |-  ( ( ph /\ k e. B ) -> ( x e. A |-> ( F x. H ) ) e. ( A -cn-> CC ) ) | 
						
							| 22 | 1 | oveq1i |  |-  ( A -cn-> CC ) = ( ( L [,] U ) -cn-> CC ) | 
						
							| 23 | 21 22 | eleqtrdi |  |-  ( ( ph /\ k e. B ) -> ( x e. A |-> ( F x. H ) ) e. ( ( L [,] U ) -cn-> CC ) ) | 
						
							| 24 |  | cnicciblnc |  |-  ( ( L e. RR /\ U e. RR /\ ( x e. A |-> ( F x. H ) ) e. ( ( L [,] U ) -cn-> CC ) ) -> ( x e. A |-> ( F x. H ) ) e. L^1 ) | 
						
							| 25 | 18 19 23 24 | syl3anc |  |-  ( ( ph /\ k e. B ) -> ( x e. A |-> ( F x. H ) ) e. L^1 ) | 
						
							| 26 | 6 17 25 | itgmulc2 |  |-  ( ( ph /\ k e. B ) -> ( G x. S. A ( F x. H ) _d x ) = S. A ( G x. ( F x. H ) ) _d x ) | 
						
							| 27 | 26 | eqcomd |  |-  ( ( ph /\ k e. B ) -> S. A ( G x. ( F x. H ) ) _d x = ( G x. S. A ( F x. H ) _d x ) ) | 
						
							| 28 | 27 | sumeq2dv |  |-  ( ph -> sum_ k e. B S. A ( G x. ( F x. H ) ) _d x = sum_ k e. B ( G x. S. A ( F x. H ) _d x ) ) |