no code implementations • 1 Oct 2021 • Ioannis Caragiannis, Karl Fehrs
Despite the existence of exponentially many outcomes compared to single-winner elections, we show that the sample complexity is still low: a polynomial number of samples carries enough information for learning the target rule with high confidence and accuracy.
no code implementations • 15 Feb 2021 • Ioannis Caragiannis, Panagiotis Kanellopoulos, Maria Kyropoulou
iEF is a natural generalization of envy-freeness to random allocations in the sense that a deterministic envy-free allocation is iEF (when viewed as a degenerate lottery).
Fairness Computer Science and Game Theory
no code implementations • 5 Feb 2020 • Ioannis Caragiannis, Christos Kaklamanis, Nikos Karanikolas, George A. Krimpas
These models take as input a ground truth committee and return random approval votes to be thought of as noisy estimates of the ground truth.
no code implementations • 18 Sep 2016 • Ioannis Caragiannis, Xenophon Chatzigeorgiou, George A. Krimpas, Alexandros A. Voudouris
Then, the important optimization problem to be solved is to compute the positional scoring rule whose outcome, when applied to the profile of individual rankings, is as close as possible to the part of the underlying true ranking we know.
no code implementations • 25 Feb 2016 • Ioannis Caragiannis, George A. Krimpas, Alexandros A. Voudouris
When statistical information about the grading behaviour of students is available (in terms of a noise matrix that characterizes the grading behaviour of the average student from a student population), the framework can be used to compute the optimal rule from this class with respect to a series of performance objectives that compare the ranking returned by the aggregation rule to the underlying ground truth ranking.
no code implementations • 13 Feb 2015 • Ioannis Caragiannis, Xenophon Chatzigeorgiou, Panagiotis Kanellopoulos, George A. Krimpas, Nikos Protopapas, Alexandros A. Voudouris
Motivated by recent progress on pricing in the AI literature, we study marketplaces that contain multiple vendors offering identical or similar products and unit-demand buyers with different valuations on these vendors.
no code implementations • 17 Nov 2014 • Ioannis Caragiannis, George A. Krimpas, Alexandros A. Voudouris
This is a novel application area for social choice concepts and methods where the important problem to be solved is as follows: how should the assignments be distributed so that the collected individual rankings can be easily merged into a global one that is as close as possible to the ranking that represents the relative performance of the students in the assignment?