ing ji ang , ▁China . ▁He ▁completed ▁his ▁under grad uate ▁studies ▁in ▁the ▁Department ▁of ▁Mathemat ics ▁at ▁University ▁of ▁Science ▁and ▁Technology ▁of ▁China ▁in ▁ 1 9 8 2 , ▁and ▁his ▁master ' s ▁degree ▁in ▁Academy ▁of ▁Mathemat ics ▁and ▁Systems ▁Science ▁at ▁Chinese ▁Academy ▁of ▁Sciences ▁in ▁ 1 9 8 5 . ▁He ▁obtained ▁his ▁Ph . D . ▁degree ▁under ▁the ▁advice ▁of ▁B jör n ▁Eng qu ist ▁in ▁the ▁Department ▁of ▁Mathemat ics ▁at ▁University ▁of ▁California , ▁Los ▁Angeles ▁in ▁ 1 9 8 9 . ▁He ▁then ▁became ▁a ▁visit ing ▁member ▁in ▁Cour ant ▁Institute , ▁New ▁York ▁University ▁from ▁ 1 9 8 9 ▁to ▁ 1 9 9 1 , ▁and ▁a ▁member ▁in ▁Institute ▁for ▁Advanced ▁Study ▁from ▁ 1 9 9 1 ▁to ▁ 1 9 9 2 . ▁After ▁sp ending ▁two ▁more ▁years ▁as ▁a ▁long ▁term ▁member ▁in ▁Institute ▁for ▁Advanced ▁Study , ▁he ▁joined ▁Cour ant ▁Institute , ▁New ▁York ▁University ▁as ▁an ▁associate ▁professor ▁in ▁ 1 9 9 4 , ▁and ▁became ▁a ▁full ▁professor ▁in ▁ 1 9 9 7 . ▁Since ▁ 1 9 9 9 , ▁he ▁has ▁been ▁holding ▁a ▁professor ship ▁in ▁the ▁Department ▁of ▁Mathemat ics ▁and ▁Program ▁in ▁App lied ▁and ▁Comput ational ▁Mathemat ics ▁at ▁Pr inc eton ▁University . ▁He ▁has ▁also ▁been ▁holding ▁a ▁professor ship ▁in ▁the ▁Be ij ing ▁International ▁Center ▁for ▁Mathemat ical ▁Research ▁( B