Search Results for author: Alexandros Hollender

Found 5 papers, 2 papers with code

The Computational Complexity of Finding Stationary Points in Non-Convex Optimization

no code implementations13 Oct 2023 Alexandros Hollender, Manolis Zampetakis

Finding approximate stationary points, i. e., points where the gradient is approximately zero, of non-convex but smooth objective functions $f$ over unrestricted $d$-dimensional domains is one of the most fundamental problems in classical non-convex optimization.

On the Complexity of Equilibrium Computation in First-Price Auctions

no code implementations4 Mar 2021 Aris Filos-Ratsikas, Yiannis Giannakopoulos, Alexandros Hollender, Philip Lazos, Diogo Poças

We consider the problem of computing a (pure) Bayes-Nash equilibrium in the first-price auction with continuous value distributions and discrete bidding space.

Computer Science and Game Theory Computational Complexity

The Complexity of Gradient Descent: CLS = PPAD $\cap$ PLS

1 code implementation3 Nov 2020 John Fearnley, Paul W. Goldberg, Alexandros Hollender, Rahul Savani

We study search problems that can be solved by performing Gradient Descent on a bounded convex polytopal domain and show that this class is equal to the intersection of two well-known classes: PPAD and PLS.

Optimally Deceiving a Learning Leader in Stackelberg Games

no code implementations NeurIPS 2020 Georgios Birmpas, Jiarui Gan, Alexandros Hollender, Francisco J. Marmolejo-Cossío, Ninad Rajgopal, Alexandros A. Voudouris

For this strategic behavior to be successful, the main challenge faced by the follower is to pinpoint the payoffs that would make the learning algorithm compute a commitment so that best responding to it maximizes the follower's utility, according to his true payoffs.

MergeShuffle: A Very Fast, Parallel Random Permutation Algorithm

2 code implementations13 Aug 2015 Axel Bacher, Olivier Bodini, Alexandros Hollender, Jérémie Lumbroso

We also show how it is possible to further reduce the number of random bits consumed, by introducing a second algorithm BalancedShuffle, a variant of the Rao-Sandelius algorithm which is more conservative in the way it recursively partitions arrays to be shuffled.

Data Structures and Algorithms Discrete Mathematics

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