Search Results for author: Grigoris Velegkas

Found 5 papers, 0 papers with code

Replicable Learning of Large-Margin Halfspaces

no code implementations21 Feb 2024 Alkis Kalavasis, Amin Karbasi, Kasper Green Larsen, Grigoris Velegkas, Felix Zhou

Departing from the requirement of polynomial time algorithms, using the DP-to-Replicability reduction of Bun, Gaboardi, Hopkins, Impagliazzo, Lei, Pitassi, Sorrell, and Sivakumar [STOC, 2023], we show how to obtain a replicable algorithm for large-margin halfspaces with improved sample complexity with respect to the margin parameter $\tau$, but running time doubly exponential in $1/\tau^2$ and worse sample complexity dependence on $\epsilon$ than one of our previous algorithms.

Statistical Indistinguishability of Learning Algorithms

no code implementations23 May 2023 Alkis Kalavasis, Amin Karbasi, Shay Moran, Grigoris Velegkas

When two different parties use the same learning rule on their own data, how can we test whether the distributions of the two outcomes are similar?

Multiclass Learnability Beyond the PAC Framework: Universal Rates and Partial Concept Classes

no code implementations5 Oct 2022 Alkis Kalavasis, Grigoris Velegkas, Amin Karbasi

Second, we consider the problem of multiclass classification with structured data (such as data lying on a low dimensional manifold or satisfying margin conditions), a setting which is captured by partial concept classes (Alon, Hanneke, Holzman and Moran, FOCS '21).

Replicable Bandits

no code implementations4 Oct 2022 Hossein Esfandiari, Alkis Kalavasis, Amin Karbasi, Andreas Krause, Vahab Mirrokni, Grigoris Velegkas

Similarly, for stochastic linear bandits (with finitely and infinitely many arms) we develop replicable policies that achieve the best-known problem-independent regret bounds with an optimal dependency on the replicability parameter.

Multi-Armed Bandits

The Best of Both Worlds: Reinforcement Learning with Logarithmic Regret and Policy Switches

no code implementations3 Mar 2022 Grigoris Velegkas, Zhuoran Yang, Amin Karbasi

In this paper, we study the problem of regret minimization for episodic Reinforcement Learning (RL) both in the model-free and the model-based setting.

reinforcement-learning Reinforcement Learning (RL)

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