▁Pet row sky ) ▁was ▁a ▁Soviet ▁math ematic ian ▁working ▁mainly ▁in ▁the ▁field ▁of ▁partial ▁differential ▁equations . ▁He ▁greatly ▁contributed ▁to ▁the ▁solution ▁of ▁Hil bert ' s ▁ 1 9 th ▁and ▁ 1 6 th ▁problems , ▁and ▁discovered ▁what ▁are ▁now ▁called ▁Pet rov sky ▁lac unas . ▁He ▁also ▁worked ▁on ▁the ▁theories ▁of ▁boundary ▁value ▁problems , ▁probability , ▁and ▁on ▁the ▁topology ▁of ▁algebraic ▁curves ▁and ▁surfaces . ▁ ▁Biography ▁▁ ▁Pet rov sky ▁was ▁a ▁student ▁of ▁D mit ri ▁Eg or ov . ▁Among ▁his ▁students ▁were ▁Ol ga ▁Lady zh ensk aya , ▁Y ev gen iy ▁Land is , ▁Ol ga ▁O lein ik ▁and ▁Serge i ▁God un ov . ▁ ▁Pet rov sky ▁taught ▁at ▁Ste k lov ▁Institute ▁of ▁Mathemat ics . ▁He ▁was ▁a ▁member ▁of ▁the ▁Soviet ▁Academy ▁of ▁Sciences ▁since ▁ 1 9 4 6 ▁and ▁was ▁awarded ▁Hero ▁of ▁Social ist ▁Labor ▁in ▁ 1 9 6 9 . ▁He ▁was ▁the ▁president ▁of ▁Moscow ▁State ▁University ▁( 1 9 5 1 – 1 9 7 3 ) ▁and ▁the ▁head ▁of ▁the ▁International ▁Congress ▁of ▁Mathemat icians ▁( M osc ow , ▁ 1 9 6 6 ). ▁He ▁is ▁buried ▁in ▁the ▁c emetery ▁of ▁the ▁Nov ode v ich y ▁Con vent ▁in ▁Moscow . ▁ ▁Selected ▁publications ▁. ▁. ▁. ▁ ▁. ▁. ▁ ▁References ▁▁ ▁. ▁A ▁very ▁am ple ▁paper ▁describing ▁Pet rov sky ' s ▁scientific