The function takes as input a list of vectors and returns the same list ordered in a lexicographical way.
For example if the input list is (2,2,3),(3,2,3),(1,2,3), then the output of the function lSort produces the following result:
(1,2,3),(2,2,3),(3,2,3).
References
Flajolet, P., and Sedgewick, R. (2009) Analytic combinatorics. Cambridge University press.