A cycle lemma for permutation inversions Original Research Article

In this paper we study some properties of the inversion statistic. Some enumerative results concerning the permutations of the multiset {x1m1,x2m2} with respect to the inversion parameter are established and it is shown that these depend on gcd(m1,m2). Using a “cycle lemma”, a combinatorial proof of the results is given. Moreover, some applications to the Gaussian binomial coefficient are illustrated.