▁of ▁Paul ▁D ien es . ▁His ▁Ph D ▁th esis , ▁entitled ▁Inter val ▁Function s ▁and ▁their ▁Integr als , ▁was ▁submitted ▁in ▁December ▁ 1 9 4 8 . ▁His ▁Ph . D . ▁exam in ers ▁were ▁Bur kill ▁and ▁H . ▁K est el man . ▁In ▁ 1 9 4 7 ▁he ▁returned ▁briefly ▁to ▁Cambridge ▁to ▁complete ▁the ▁under grad uate ▁mathematical ▁studies ▁which ▁had ▁been ▁trunc ated ▁by ▁his ▁Ministry ▁of ▁Supp ly ▁work . ▁ ▁Most ▁of ▁Hen stock ' s ▁work ▁was ▁concerned ▁with ▁integration . ▁From ▁initial ▁studies ▁of ▁the ▁Bur kill ▁and ▁Ward ▁integr als ▁he ▁form ulated ▁an ▁integration ▁process ▁where by ▁the ▁domain ▁of ▁integration ▁is ▁suit ably ▁partition ed ▁for ▁Riemann ▁sums ▁to ▁approximate ▁the ▁integral ▁of ▁a ▁function . ▁His ▁methods ▁led ▁to ▁an ▁integral ▁on ▁the ▁real ▁line ▁that ▁was ▁very ▁similar ▁in ▁construction ▁and ▁simplicity ▁to ▁the ▁Riemann ▁integral ▁but ▁which ▁included ▁the ▁Leb es gue ▁integral ▁and , ▁in ▁addition , ▁allowed ▁non - absolute ▁convergence . ▁ ▁These ▁ideas ▁were ▁developed ▁from ▁the ▁late ▁ 1 9 5 0 s . ▁Independ ently , ▁Jar oslav ▁Kurz we il ▁developed ▁a ▁similar ▁Riemann - type ▁integral ▁on ▁the ▁real ▁line . ▁The ▁resulting ▁integral ▁is ▁now ▁known ▁as ▁the ▁Hen stock - K urz we il ▁integral . ▁On ▁the ▁real ▁line ▁it ▁is ▁equivalent ▁to ▁the ▁Den jo y - Per ron ▁integral , ▁but ▁has ▁a ▁simpler ▁definition . ▁ ▁In