8 papers
A Better-than-2 Approximation for k-Median Part I: The Power of General Bids
Rares-Darius Buhai, Vincent Cohen-Addad, Henry Fleischmann +6
The Greedy algorithm of Jain, Mahdian, Markakis, Saberi, and Vazirani was the best Lagrangian-multiplier-preserving (LMP) approximation algorithm for facility location, and thus th…
A Better-than- Approximation for -Median Part II: Stable Instances
Rares-Darius Buhai, Vincent Cohen-Addad, Henry Fleischmann +6
We consider the -median problem on general metric spaces, subject to the condition that the instances are -stable (i.e., the optimal solution using centers has a cost a…
Space-Efficient Language Generation in the Limit
Nicolas Flammarion, Chirag Pabbaraju, Hristo Papazov +2
We initiate a resource-aware theory of \textit{language generation in the limit} under the minimal constraint of space efficiency. In our framework, a learner observes an adversari…
Retriever Portfolios: A Principled Approach to Adaptive RAG
Miltiadis Stouras, Vincent Cohen-Addad, Silvio Lattanzi +1
Retrieval-augmented generation (RAG) systems typically rely on a single retriever and a single set of hyperparameters, despite facing highly heterogeneous queries that range from s…
An Optimal Algorithm for Stochastic Vertex Cover
Jan van den Brand, Inge Li Gørtz, Chirag Pabbaraju +5
The goal in the stochastic vertex cover problem is to obtain an approximately minimum vertex cover for a graph that is realized by sampling each edge independently with s…
Online Two-Stage Submodular Maximization
Iasonas Nikolaou, Miltiadis Stouras, Stratis Ioannidis +1
Given a collection of monotone submodular functions, the goal of Two-Stage Submodular Maximization (2SSM) [Balkanski et al., 2016] is to restrict the ground set so an objective sel…
Data-Driven Solution Portfolios
Marina Drygala, Silvio Lattanzi, Andreas Maggiori +3
In this paper, we consider a new problem of portfolio optimization using stochastic information. In a setting where there is some uncertainty, we ask how to best select potenti…
Graph Connectivity with Noisy Queries
Dimitris Fotakis, Evangelia Gergatsouli, Charilaos Pipis +2
Graph connectivity is a fundamental combinatorial optimization problem that arises in many practical applications, where usually a spanning subgraph of a network is used for its op…