sign i ▁is ▁also ▁very ▁proud ▁of ▁an ▁elegant ▁well - head ▁of ▁the ▁same ▁period , ▁attributed ▁by ▁some ▁to ▁Bern ini , ▁which ▁it ▁has ▁adopted ▁as ▁its ▁symbol . ▁ ▁References ▁ ▁External ▁links ▁U sign i ▁( Th ayer ' s ▁Gazette er ▁of ▁Um b ria ) ▁ ▁Category : F raz ioni ▁of ▁the ▁Province ▁of ▁Per ug ia ▁Category : H ill town s ▁in ▁Um b ria <0x0A> </s> ▁Arnold ▁F . ▁Em ch ▁( 2 4 ▁March ▁ 1 8 7 1 ▁– ▁ 1 9 5 9 ) ▁was ▁an ▁American ▁math ematic ian , ▁known ▁for ▁his ▁work ▁on ▁the ▁ins cribed ▁square ▁problem . ▁ ▁Em ch ▁received ▁his ▁Ph . D . ▁in ▁ 1 8 9 5 ▁at ▁the ▁University ▁of ▁Kansas ▁under ▁the ▁super vision ▁of ▁Henry ▁By ron ▁New son . ▁In ▁the ▁late ▁ 1 8 9 0 s ▁until ▁ 1 9 0 5 ▁he ▁was ▁an ▁assistant ▁professor ▁of ▁graph ic ▁mathematics ▁in ▁the ▁school ▁of ▁engineering ▁at ▁the ▁Kansas ▁State ▁Agricult ural ▁College ▁( now ▁Kansas ▁State ▁University ). ▁In ▁ 1 9 0 5 ▁Em ch ▁became ▁a ▁professor ▁of ▁mathematics ▁at ▁the ▁Kant ons schule ▁in ▁Sol oth urn , ▁Switzerland . ▁In ▁ 1 9 0 8 ▁Em ch ▁gave ▁a ▁lecture ▁at ▁the ▁International ▁Congress ▁of ▁Mathemat icians ▁in ▁Rome . ▁From ▁ 1 9 1 1 ▁to ▁ 1 9 3 9 ▁he ▁was ▁a ▁professor ▁at ▁the