COMBIMA: truthful, budget maintaining, dynamic combinatorial market

Current interest in two-sided markets is motivated by examples of successful practical applications of market mechanisms in supply chain markets, online advertising exchanges, and pollution-rights markets. Many of these examples require markets where agents arrive dynamically and can trade multiple commodities. However, the known literature largely focuses on settings with single-commodity unit demand. We present, prove and evaluate a general solution that matches agents in a dynamic, two-sided combinatorial market. Multiple commodities, each with multiple units, are bought and sold in different bundles by agents that arrive over time. Our mechanism, COMBIMA, provides the first dynamic two-sided combinatorial market that allows truthful and individually-rational behavior for all agents, keeps the market budget balanced and approximates social welfare efficiency.We experimentally examine and compare the allocative efficiency of COMBIMA with respect to our proven theoretical bounds and with respect to all known (dynamic and non-dynamic) social-welfare maximizing two-sided markets under variety of distributions of bids, market demands and market size. COMBIMA performs well by all benchmarks and in many cases improves on previous mechanisms.