This introductory essay briefly summarizes the eleven empirical studies of price setting and price adjustment that are included in this special issue. The studies, which use data from several European countries, were conducted as part of the European Central Bank's Inflation Persistence Network.

The multiple-choice nested knapsack problem (MCKP) is a generalization of the ordinary knapsack problem, where the set of items is partitioned into classes. The binary choice of selecting an item is replaced by taking exactly one item out of each class of items. Due to the fact that the MCKP is...

The generalized assignment problem (GAP) examines the maximum profit assignment of jobs to processors such that each job is assigned to precisely one processor subject to capacity restrictions on the processors. Due to the fact that the GAP is an NP-hard integer program dual prices are not...