10 citations · 24 across the 15 of their papers we have counts for
23 papers
On the Power of Determinism in Multi-Item Auctions
Yiannis Giannakopoulos, Johannes Hahn
We study the classical multi-item monopoly setting with a single additive buyer and heterogeneous items whose values are independent but not necessarily identically distributed…
Efficient Equilibrium Computation in Symmetric First-Price Auctions
Aris Filos-Ratsikas, Yiannis Giannakopoulos, Alexandros Hollender +1
We study the complexity of computing Bayes-Nash equilibria in single-item first-price auctions. We present the first efficient algorithms for the problem, when the bidders' values…
Equilibrium Computation in First-Price Auctions with Correlated Priors
Aris Filos-Ratsikas, Yiannis Giannakopoulos, Alexandros Hollender +1
We consider the computational complexity of computing Bayes-Nash equilibria in first-price auctions, where the bidders' values for the item are drawn from a general (possibly corre…
Discrete Single-Parameter Optimal Auction Design
Yiannis Giannakopoulos, Johannes Hahn
We study the classic single-item auction setting of Myerson, but under the assumption that the buyers' values for the item are distributed over finite supports. Using strong LP dua…
On the Computation of Equilibria in Discrete First-Price Auctions
Aris Filos-Ratsikas, Yiannis Giannakopoulos, Alexandros Hollender +1
We study the computational complexity of computing Bayes-Nash equilibria in first-price auctions with discrete value distributions and discrete bidding space, under general subject…
A Smoothed FPTAS for Equilibria in Congestion Games
Yiannis Giannakopoulos
We present a fully polynomial-time approximation scheme (FPTAS) for computing equilibria in congestion games, under smoothed running-time analysis. More precisely, we prove that if…
On the Smoothed Complexity of Combinatorial Local Search
Yiannis Giannakopoulos, Alexander Grosz, Themistoklis Melissourgos
We propose a unifying framework for smoothed analysis of combinatorial local optimization problems, and show how a diverse selection of problems within the complexity class PLS can…
On the Complexity of Equilibrium Computation in First-Price Auctions
Aris Filos-Ratsikas, Yiannis Giannakopoulos, Alexandros Hollender +2
We consider the problem of computing a (pure) Bayes-Nash equilibrium in the first-price auction with continuous value distributions and discrete bidding space. We prove that when b…
A Unifying Approximate Potential for Weighted Congestion Games
Yiannis Giannakopoulos, Diogo Poças
We provide a unifying, black-box tool for establishing existence of approximate equilibria in weighted congestion games and, at the same time, bounding their Price of Stability. Ou…
A New Lower Bound for Deterministic Truthful Scheduling
Yiannis Giannakopoulos, Alexander Hammerl, Diogo Poças
We study the problem of truthfully scheduling tasks to selfish unrelated machines, under the objective of makespan minimization, as was introduced in the seminal work of Ni…
Existence and Complexity of Approximate Equilibria in Weighted Congestion Games
George Christodoulou, Martin Gairing, Yiannis Giannakopoulos +2
We study the existence of approximate pure Nash equilibria (-PNE) in weighted atomic congestion games with polynomial cost functions of maximum degree . Previously it was kno…
Robust Revenue Maximization Under Minimal Statistical Information
Yiannis Giannakopoulos, Diogo Poças, Alexandros Tsigonias-Dimitriadis
We study the problem of multi-dimensional revenue maximization when selling items to a buyer that has additive valuations for them, drawn from a (possibly correlated) prior dis…
Computing Approximate Equilibria in Weighted Congestion Games via Best-Responses
Yiannis Giannakopoulos, Georgy Noarov, Andreas S. Schulz
We present a deterministic polynomial-time algorithm for computing -approximate (pure) Nash equilibria in (proportional sharing) weighted congestion games with polynomi…
Optimal Pricing For MHR and -Regular Distributions
Yiannis Giannakopoulos, Diogo Poças, Keyu Zhu
We study the performance of anonymous posted-price selling mechanisms for a standard Bayesian auction setting, where bidders have i.i.d. valuations for a single item. We show t…
The Pareto Frontier of Inefficiency in Mechanism Design
Aris Filos-Ratsikas, Yiannis Giannakopoulos, Philip Lazos
We study the trade-off between the Price of Anarchy (PoA) and the Price of Stability (PoS) in mechanism design, in the prototypical problem of unrelated machine scheduling. We give…
The Price of Stability of Weighted Congestion Games
George Christodoulou, Martin Gairing, Yiannis Giannakopoulos +1
We give exponential lower bounds on the Price of Stability (PoS) of weighted congestion games with polynomial cost functions. In particular, for any positive integer we constru…
Online Market Intermediation
Yiannis Giannakopoulos, Elias Koutsoupias, Philip Lazos
We study a dynamic market setting where an intermediary interacts with an unknown large sequence of agents that can be either sellers or buyers: their identities, as well as the se…
The Anarchy of Scheduling Without Money
Yiannis Giannakopoulos, Elias Koutsoupias, Maria Kyropoulou
We consider the scheduling problem on strategic unrelated machines when no payments are allowed, under the objective of minimizing the makespan. We adopt the model introduced i…
Selling Two Goods Optimally
Yiannis Giannakopoulos, Elias Koutsoupias
We provide sufficient conditions for revenue maximization in a two-good monopoly where the buyer's values for the items come from independent (but not necessarily identical) distri…
The VCG Mechanism for Bayesian Scheduling
Yiannis Giannakopoulos, Maria Kyropoulou
We study the problem of scheduling tasks to selfish, unrelated machines in order to minimize the makespan, where the execution times are independent random variables, ident…
A Note on Selling Optimally Two Uniformly Distributed Goods
Yiannis Giannakopoulos
We provide a new, much simplified and straightforward proof to a result of Pavlov [2011] regarding the revenue maximizing mechanism for selling two goods with uniformly i.i.d. valu…
Bounding the Optimal Revenue of Selling Multiple Goods
Yiannis Giannakopoulos
Using duality theory techniques we derive simple, closed-form formulas for bounding the optimal revenue of a monopolist selling many heterogeneous goods, in the case where the buye…
Duality and Optimality of Auctions for Uniform Distributions
Yiannis Giannakopoulos, Elias Koutsoupias
We develop a general duality-theory framework for revenue maximization in additive Bayesian auctions. The framework extends linear programming duality and complementarity to constr…