Counting techniques to label constant weight Gray codes with links to minimal generating sets of semigroups (Q1403878)

The authors continue their study on the orthogonal labeling of constant weight Gray codes, started in the paper reviewed above. The combinatorics and semigroup theory aspects are treated independently again. Among others, the authors generalize a known result on the rank and idempotent rank of the semigroup of transformations of \(\{1,2,\dots, n\}\) containing at most \(r\) elements in the image.