, ▁University ▁of ▁California ▁at ▁Ber keley , ▁the ▁Institute ▁of ▁Advanced ▁Study ▁in ▁Pr inc eton , ▁U CLA , ▁Oxford ▁University , ▁Cambridge ▁University , ▁the ▁Max ▁Plan ck ▁Institute ▁and ▁University ▁of ▁Paris . ▁In ▁ 1 9 7 8 , ▁he ▁gave ▁one ▁of ▁the ▁invited ▁tal ks ▁at ▁the ▁International ▁Congress ▁of ▁Mathemat icians ▁in ▁Hels ink i . ▁In ▁ 1 9 9 9 , ▁he ▁spoke ▁about ▁some ▁aspects ▁of ▁the ▁work ▁of ▁André ▁We il ▁on ▁the ▁occasion ▁of ▁his ▁being ▁awarded ▁the ▁In am ouri ▁Prize . ▁ ▁Ram an an ▁discovered ▁and ▁encourag ed ▁V ij ay ▁K umar ▁Pat odi , ▁who ▁proved ▁part ▁of ▁the ▁A ti y ah - S inger ▁index ▁theorem , ▁Pat odi ▁did ▁his ▁Ph d ▁under ▁the ▁combined ▁direction ▁of ▁Nar as im han ▁and ▁Ram an an . ▁Ram an an ▁was ▁MS ▁R agh un athan ' s ▁senior ▁colle ague ▁and ▁influenced ▁him ▁consider ably . ▁ ▁Ram an an ▁wrote ▁the ▁book ▁Mod uli ▁of ▁Ab elian ▁Vari eties ▁with ▁All an ▁Ad ler , ▁published ▁by ▁Springer - Verlag , ▁and ▁a ▁gradu ate - level ▁book ▁on ▁algebraic ▁geometry ▁called ▁Global ▁Calcul us , ▁published ▁by ▁the ▁American ▁Mathemat ical ▁Society . ▁He ▁continues ▁his ▁contributions ▁via ▁teaching ▁and ▁ment oring ▁at ▁the ▁Chen na i ▁Mathemat ical ▁Institute , ▁where ▁he ▁is ▁adj unct ▁professor , ▁and ▁at ▁the ▁Institute ▁of ▁Mathemat ical ▁Sciences , ▁Chen na i