Rose Peltesohn

Life

Rose Peltesohn was the daughter of the physician Ludwig Peltesohn (1882–1937) and of Cilly Caro. After graduation (Abitur) in March 1931 she studied mathematics and physics at the University of Berlin and got her Ph.D. in Mathematics at 1936 with Issai Schur as supervisor (Das Turnierproblem für Spiele zu je dreien, The tournament problem for three person games). Her dissertation was valued opus valde laudabile^(de). Being Jewish she emigrated through Italy to Palestine, arriving 1938. Between the years 1939–1942 she worked in a bank and later as a lawyer's secretary and translator in Tel Aviv. She married her cousin Gerhard Peltesohn, a lawyer (1909–1965), and both had two daughters, Ruth (born 1940) and Judith (born 1943).

Solution of Heffter's Difference Problems

Peltesohn solved the Difference Problems of Lothar Heffter (1896) in combinatorics in 1939. A Difference Triple (a, b, c) is defined as three different elements from the set 1 , 2 , … , v − 1 , whose sum mod v equals zero ( a + b + c = 0 mod v ) or for which one element mod v equals the sum of the other two ( a + b = c mod v ).

Following Peltesohn, such a partition exists with the exception of the case v = 9.

An example of the partition for v = 13 is: ( 1 , 3 , 4 ) (with 1 + 3 = 4 mod 1 3 ) and ( 2 , 5 , 6 ) (with 2 + 5 + 6 = 13 = 0 mod 1 3 ).

The solution of the Difference Problem of Heffter also gives a construction of cyclic Steiner triple systems.

Literature