$λ$-fold near-factorizations of groups

Abstract: We initiate the study of $\lambda$-fold near-factorizations of groups with $\lambda > 1$. While $\lambda$-fold near-factorizations of groups with $\lambda = 1$ have been studied in numerous papers, this is the first detailed treatment for $\lambda > 1$. We establish fundamental properties of $\lambda$-fold near-factorizations and introduce the notion of equivalence. We prove various necessary conditions of $\lambda$-fold near-factorizations, including upper bounds on $\lambda$. We present three constructions of infinite families of $\lambda$-fold near-factorizations, highlighting the characterization of two subfamilies of $\lambda$-fold near-factorizations. We discuss a computational approach to $\lambda$-fold near-factorizations and tabulate computational results for abelian groups of small order.