ski ▁obtained ▁Swiss ▁citizens hip . ▁After ▁ret irement ▁he ▁still ▁published ▁scientific ▁papers ▁until ▁his ▁late ▁eight ies . ▁ ▁See ▁also ▁Ost row ski ' s ▁theorem ▁Ost row ski – H ad am ard ▁gap ▁theorem ▁Ost row ski ▁numer ation ▁Ost row ski ▁Prize ▁ ▁External ▁links ▁Ost row ski ▁Foundation ▁website : ▁short ▁bi ography ▁ ▁G aut sch i , ▁Walter , ▁Alexander ▁M . ▁Ost row ski ▁( 1 8 9 3 - 1 9 8 6 ): ▁His ▁life , ▁work , ▁and ▁students ▁ ▁Category : Function al ▁anal yst s ▁Category : Operator ▁the or ists ▁Category : Math emat ical ▁anal yst s ▁Category : N umer ical ▁anal yst s ▁Category : Al gebra ists ▁Category : 2 0 th - century ▁mathemat icians ▁Category : J ew ish ▁scient ists ▁Category : 1 8 9 3 ▁birth s ▁Category : 1 9 8 6 ▁death s ▁Category : Pe ople ▁from ▁K iev ▁Category : U k rain ian ▁Jews ▁Category : Im per ial ▁Russian ▁Jews ▁Category : U k rain ian ▁mathemat icians <0x0A> </s> ▁The ▁Revolution ▁of ▁Y ung ▁Hav oks ▁is ▁the ▁first ▁solo ▁album ▁by ▁American ▁ra pper ▁V ord ul ▁M ega , ▁released ▁on ▁Nature ▁S ounds ▁in ▁ 2 0 0 4 . ▁ ▁Track ▁listing ▁ ▁References ▁ ▁External ▁links ▁▁▁ ▁Category : 2 0 0 4 ▁debut ▁albums ▁Category : V ord ul ▁M ega ▁albums ▁Category : N ature