Users are supposed to load the program "pCurvature.mgm" from https://github.com/schost/pCurvature first, then the file "desing" and finally examples. 

A difference operator is written in the form of a list for the program to recognize it. For example, 
	L := 1 + 2 * tau + x * tau^3
should be written as
	L := [ 1, 2, 0, x]