Abstract :
We investigate here the quasiordering ⩽ of finite sets of finite strings over an infinite set of symbols S. We set K ⩽ L iff it is possible to rename symbols occurring in the srings of L so that any string of K is a subsequence of a string of the renamed L. We prove that ⩽ is a wqo which answers the question raised by Gustedt (1992). We prove also a stronger version with injective correspondence between strings.
