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Main Authors: Bertram, Noah, Lai, Tean, Hsu, Justin
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.14068
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author Bertram, Noah
Lai, Tean
Hsu, Justin
author_facet Bertram, Noah
Lai, Tean
Hsu, Justin
contents Envy-free cake-cutting protocols procedurally divide an infinitely divisible good among a set of agents so that no agent prefers another's allocation to their own. These protocols are highly complex and difficult to prove correct. Recently, Bertram, Levinson, and Hsu introduced a language called Slice for describing and verifying cake-cutting protocols. Slice programs can be translated to formulas encoding envy-freeness, which are solved by SMT. While Slice works well on smaller protocols, it has difficulty scaling to more complex cake-cutting protocols. We improve Slice in two ways. First, we show any protocol execution in Slice can be replicated using piecewise uniform valuations. We then reduce Slice's constraint formulas to formulas within the theory of linear real arithmetic, showing that verifying envy-freeness is efficiently decidable. Second, we design and implement a linear type system which enforces that no two agents receive the same part of the good. We implement our methods and verify a range of challenging examples, including the first nontrivial four-agent protocol.
format Preprint
id arxiv_https___arxiv_org_abs_2405_14068
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Verifying Cake-Cutting, Faster
Bertram, Noah
Lai, Tean
Hsu, Justin
Computer Science and Game Theory
Programming Languages
D.3.1; J.4
Envy-free cake-cutting protocols procedurally divide an infinitely divisible good among a set of agents so that no agent prefers another's allocation to their own. These protocols are highly complex and difficult to prove correct. Recently, Bertram, Levinson, and Hsu introduced a language called Slice for describing and verifying cake-cutting protocols. Slice programs can be translated to formulas encoding envy-freeness, which are solved by SMT. While Slice works well on smaller protocols, it has difficulty scaling to more complex cake-cutting protocols. We improve Slice in two ways. First, we show any protocol execution in Slice can be replicated using piecewise uniform valuations. We then reduce Slice's constraint formulas to formulas within the theory of linear real arithmetic, showing that verifying envy-freeness is efficiently decidable. Second, we design and implement a linear type system which enforces that no two agents receive the same part of the good. We implement our methods and verify a range of challenging examples, including the first nontrivial four-agent protocol.
title Verifying Cake-Cutting, Faster
topic Computer Science and Game Theory
Programming Languages
D.3.1; J.4
url https://arxiv.org/abs/2405.14068