Stable Task Allocation in Multi-Agent Systems with Lexicographic Preferences

Motivated by the increasing interest in the explicit representation and handling of various "preference" structures arising in modern digital economy, this work introduces a new class of "one-to-many stable-matching" problems where a set of atomic tasks must be stably allocated to a set of agents. An important characteristic of these stable-matching problems is the very arbitrary specification of the task subsets constituting "feasible" allocations for each agent. It is shown that as long as the agents rank their feasible task allocations lexicographically with respect to their stated preferences for each atomic task, matching stability reduces to the absence of blocking agent-task pairs. This result, together with a pertinent graphical representation of feasible allocations, enable (i) the representation of the space of stable matchings as a set of linear constraints with binary variables, and (ii) the specification and handling of certain notions of optimality within this space of stable matchings. The last part of the paper also addresses the notion of "substitutability" in the considered problem context.