On the Stanley length of monomial ideals

Abstract: Let $S=K[x_1,\ldots,x_n]$ be the ring of polynomials in $n$ variables over an arbitrary field $K$. Given a finitely generated multigraded module $M$, its Stanley length, denoted by $\operatorname{slength}(M)$, is the minimal length of a Stanley decomposition of $M$. We prove several results regarding this new invariant. For instance, if $I\subset S$ is a monomial ideal, we give an upper bound for $\operatorname{slength}(I)$, in terms of its minimal monomial generators. Also, we show that if $I$ is minimally generated by $m$ monomials, and has linear quotients, then $\operatorname{slength}(I)=m$, and the converse holds in some special cases.