ing ey r ark la ust ur ) ▁S nor r ason ▁Hold ings , ▁I cel and ic ▁holding ▁company ▁with ▁primary ▁interests ▁in ▁online ▁payment ▁processing ▁S nor ri ▁S nor r ason ▁( born ▁ 1 9 7 7 ), ▁I cel and ic ▁singer ▁who ▁rose ▁to ▁popular ity ▁after ▁winning ▁Id ol ▁St jör n ule it ▁ 3 , ▁the ▁I cel and ic ▁version ▁of ▁Pop ▁Id ol <0x0A> </s> ▁Ale k se i ▁Z in ov ye v ich ▁Pet rov ▁( ; ▁ 2 8 ▁October ▁( 1 5 ▁October , ▁Old ▁Style ) ▁ 1 9 1 0 , ▁K osh ki , ▁Sam ara ▁Governor ate , ▁Russian ▁Empire ▁– ▁ 9 ▁May ▁ 1 9 7 2 , ▁K iev , ▁Soviet ▁Union ) ▁was ▁a ▁math ematic ian ▁noted ▁for ▁his ▁work ▁on ▁the ▁classification ▁of ▁Ein stein ▁spaces , ▁today ▁called ▁Pet rov ▁classification . ▁▁ ▁The ▁Pet rov ▁classification ▁is ▁related ▁with ▁the ▁W ey l ▁tensor ▁and ▁it ▁was ▁first ▁published ▁by ▁A . ▁Z . ▁Pet rov ▁in ▁ 1 9 5 4 . ▁ ▁External ▁links ▁A ▁bi ography ▁of ▁Pet rov ▁from ▁Kaz an ▁State ▁University ▁ ▁Category : 1 9 1 0 ▁birth s ▁Category : 1 9 7 2 ▁death s ▁Category : Russ ian ▁mathemat icians ▁Category : 2 0 th - century ▁mathemat icians <0x0A> </s> ▁This ▁is ▁a ▁summary ▁of ▁ 1 9 6 7 ▁in ▁music ▁in ▁the