(1) AT & T Labs—Research, Florham Park, USA;(2) School of Engineering and Applied Sciences, Harvard University, Cambridge, USA
Abstract:
In this paper we introduce and study a family An(q)\mathcal{A}_{n}(q) of abelian subgroups of GLn(q){\rm GL}_{n}(q) covering every element of GLn(q){\rm GL}_{n}(q). We show that An(q)\mathcal{A}_{n}(q) contains all the centralizers of cyclic matrices and equality holds if q>n. For q>2, we obtain an infinite product expression for a probabilistic generating function for |An(q)||\mathcal{A}_{n}(q)|. This leads to upper and lower bounds which show in particular that