Daphne Petrakis

Daphne Petrakis completed her doctorate at the School of Mathematics of the Aristotle University of Thessaloniki, where her dissertation developed the mathematical foundations of stable matching in large markets. The central results extended the Gale-Shapley deferred acceptance algorithm to many-to-one and many-to-many settings with contracts and transfers, and characterised the structure of stable matchings as the market grows large through a measure-theoretic formulation in which individual agents are replaced by a continuum. The dissertation established existence and uniqueness of stable outcomes in the continuum limit under regularity conditions on the preference distribution, and derived quantitative convergence rates in Wasserstein distance for the empirical matching distribution as the number of participants grows. She subsequently held a postdoctoral fellowship at the Paris School of Economics, where she worked on the connection between matching theory and the theory of optimal transport, developing a Monge-Kantorovich duality framework for transferable utility matching markets.

Following the postdoctoral period, Petrakis investigated assortative matching in continuous-type economies, where the optimal transport duality yields a tractable characterisation of stable matchings as solutions to a linear programme on the space of joint distributions over types. She extended this framework to settings with non-transferable utility and multi-dimensional types, establishing sufficient conditions for positive assortative matching and characterising the set of stable outcomes as the extreme points of a polytope defined by stability constraints. A parallel line of work examined many-to-one matching with contracts — including substitutes conditions, monotonicity properties, and the rural hospital theorem — using a lattice-theoretic approach that generalises the Tarski fixed-point argument to the contract setting and yields constructive existence proofs.

At IADU, Petrakis contributes matching theory and market design to the Institute's applied research programme in optimal allocation and mechanism design for public-sector clients. Her work examines optimal matching frameworks for sovereign procurement and contract award processes, the design of stable allocation mechanisms for public-sector labour markets, and the application of continuous-type matching theory to the optimal assignment of regulatory obligations across heterogeneous financial institutions. She supports the mathematical foundations of IADU's research on mechanism design for sovereign and central banking clients.