@UNPUBLISHED{publication1, title = "On q-permanent expansions and a theorem on cycle surgery", author = "{MARQUES DE S{\'{A}}, Eduardo}", year = "2017-07-05", abstract = "The q-permanent linear preservers are described, and several expansion formulas for the q-permanent of a square matrix are given. Some of these formulas are valid for all matrices, but others are not; for each such formula \Φ we determine all digraphs D such that \Φ holds for all matrices with digraph D. The proof technique is based on a combinatorial result where we accurately evaluate what happens to the the number of inversions of a permutation \π when one of its cycles if excised from \π. In the last section some structural issues are raised concerning the q-permanent expansions previously studied, and some open problems are presented. ", url = "http://www.mat.uc.pt/preprints/eng\_2017.html", note = "" }