Another factor was the arrival of Marcinkiewicz in Paris in the spring of 1939. Salem collaborated with this brilliant young Polish mathematician and of the mathematics papers he wrote while working for the bank, the one he wrote with Marcinkiewicz was his only joint work.
Iba pang kadahilanan ay ang pagdating ng Marcinkiewicz sa Paris sa tagsibol ng 1939. Salem collaborated ito sa mga batang napakatalino Polish dalubbilang at matematika ng mga papeles wrote siya habang nagtatrabaho para sa bangko, siya ang isa sa mga wrote Marcinkiewicz ay kanyang lamang pinagsamang trabaho.