Papers for

real-time ad allocation teams

Papers whose findings have a practical use for this group, as judged from the abstract. Open a paper to read what it means in practice.

Improved algorithm boosts online matching with weighted edges beyond 55 percent

Online Edge-Weighted Matching Beyond 0.55

Abstract: We give a $0.556195$-competitive randomized algorithm for edge-weighted online bipartite matching with free disposal, improving the $0.5368$ guarantee of Blanc and Charikar. The result holds for arbitrary nonnegative edge weights and any input sequence fixed independently of the algorithm's randomness. Our algorithm builds on online correlated selection, introduced by Fahrbach, Huang, Tao, and Zadimoghaddam, and its multiway extension due to Blanc and Charikar. Our main contribution is a state-dependent primal--dual analysis of correlated selection. At each weight threshold, we track the state of the selection process jointly with an auxiliary failure event. The analysis accounts for arrivals below the threshold, which change the state without improving the matching value at that threshold. A potential function bounds the dual increase in both cases. We instantiate the analysis with an explicit win map that assigns a common score to an initial range of states. Its selection inequalities are verified by a finite computer-assisted proof covering every required candidate multiplicity and every real threshold; the verifiers are available in an accompanying repository. Triangular unit-weight inputs asymptotically attain the guarantee of the underlying ideal algorithm, proving that its analysis is tight.

Wed 4 NovData Structures and AlgorithmsComputer Science and Game Theory
The gist
Online matching problems ask how to pair things arriving one by one in the best possible way. This paper improves a known algorithm that tries to find the heaviest matching between two groups with weights on the connections. The new algorithm achieves better performance, about 55.6% of the optimal in tough cases, beating the previous 53.7%. It uses a sophisticated way to track choices using probabilities depending on past decisions, analyzed carefully with math tools and computer checks. This work shows the limits of this approach by matching a certain known hard example exactly.
Open → 2611.06896v1