What its about? Real-world institutions such as colleges and hospitals typically make admission decisions through committees that aggregate multiple members' preferences, rather than following a single predetermined ranking. In matching markets, the fundamental results of Hatfield and Milgrom (2005) on existence of stable outcomes and the validity of the Deferred Acceptance (DA) algorithm critically depend on college choice functions satisfying Substitutability (SUB) and the Law of Aggregate Demand (LAD). However, many natural committee voting procedures including positional scoring methods run on the current menu (e.g., Borda count, Single Transferable Vote), as well as portfolio optimization approaches that value diversity introduce context-dependent complementarities that violate these essential properties. When substitutability fails, stable matchings may cease to exist and DA loses its theoretical guarantees.

This project aims to bridge the gap between multi-winner voting theory and matching market theory by providing a complete characterization of aggregation rules that preserve market stability. We establish that committee procedures are "safe" yielding SUB and LAD satisfying choice functions if and only if they produce set-independent type-wise priority orders that do not depend on the available menu. Main results include: (1) a classification theorem identifying the class of social choice rules that guarantee SUB and LAD, thereby ensuring stable outcomes exist and DA terminates successfully; (2) tight counterexamples demonstrating that popular set-dependent procedures violate substitutability even in minimal instances; and (3) a design recipe showing how diversity and representation objectives can be safely implemented through type/slot structures with fixed priorities rather than portfolio optimization.

Technically, we leverage the equivalence between path independence and substitutability plus irrelevance of rejected contracts to characterize exactly when a choice function admits a set-independent type-wise priority representation. Our framework provides institutions with practical guidance on which committee aggregation methods preserve the theoretical foundations of stable matching while accommodating real-world concerns about fair aggregation and diversity.

Abstract: This paper develops a theoretical framework for International Kidney Paired Exchange (IKPE) to address efficiency and fairness concerns in multi-country kidney-paired exchange networks. Drawing on a discrete version of the Kalai–Smorodinsky (KS) bargaining solution, we propose a mechanism that first maximizes worst country’s relative gain, and then selects an allocation that achieves the largest overall transplant benefit. The model features a dynamic weighting scheme that adjusts over time to compensate countries whose participation yields lower gains in the past rounds compared to other countries, ensuring an equitable distribution of cooperative gains. We prove that the proposed mechanism guarantees Pareto optimality and individual rationality of the resulting allocation as no country is worse off by cooperating than by acting alone. 

Abstract: We study a model in which a sender tries to persuade a decision-maker by committing to a signaling strategy (Kamenica and Gentzkow, 2011). The decision-maker observes this and, in turn, commits to an interim verification strategy that reveals the true state of the world with an endogenously determined probability. The possibility of verification induces a trade-off for the sender: providing more information decreases the verification probability but also decreases the ex-ante persuasion payoff. The decision-maker trades off learning the state with more precision against the cost of verification. We provide the precise conditions under which introducing verification leads to (a) strictly more informative signaling, and (b) higher ex-ante welfare for the decision-maker compared to the canonical persuasion game.

Abstract: This project studies the relationship between stability and popularity in strict two-sided one-to-one matching markets. I introduce three domain axioms regulating majority comparisons on alternating paths and cycles: (DR1) odd-path endpoint-majority, (DR2) strict cycle dominance, and (DR3) uniqueness of the maximum matched set, and show that these conditions are sufficient for stability and popularity to coincide. My main theorem proves that under DR1–DR3, every popular matching is stable and, conversely, every stable matching is popular, yielding an exact equivalence between majority choice and Gale–Shapley stability. We illustrate the role of each axiom through constructed examples and show how violations of DR1 permit unstable yet weakly popular enlargements. We further analyze the master-list domain, where the stable matching is unique and forms the minimum-cardinality popular matching, and identify structural restrictions on popular matchings imposed by DR1.