On Pigeonhole Principles and Ramsey in TFNP

Fuente: arXiv
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Auteurs principaux: Jain, Siddhartha, Li, Jiawei, Robere, Robert, Xun, Zhiyang
Format: Preprint
Publié: 2024
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author Jain, Siddhartha
Li, Jiawei
Robere, Robert
Xun, Zhiyang
author_facet Jain, Siddhartha
Li, Jiawei
Robere, Robert
Xun, Zhiyang
contents We show that the TFNP problem RAMSEY is not black-box reducible to PIGEON, refuting a conjecture of Goldberg and Papadimitriou in the black-box setting. We prove this by giving reductions to RAMSEY from a new family of TFNP problems that correspond to generalized versions of the pigeonhole principle, and then proving that these generalized versions cannot be reduced to PIGEON. Formally, we define t-PPP as the class of total NP-search problems reducible to finding a t-collision in a mapping from (t-1)N+1 pigeons to N holes. These classes are closely related to multi-collision resistant hash functions in cryptography. We show that the generalized pigeonhole classes form a hierarchy as t increases, and also give a natural condition on the parameters t1, t2 that captures exactly when t1-PPP and t2-PPP collapse in the black-box setting. Finally, we prove other inclusion and separation results between these generalized PIGEON problems and other previously studied TFNP subclasses, such as PLS, PPA and PLC. Our separation results rely on new lower bounds in propositional proof complexity based on pseudoexpectation operators, which may be of independent interest.
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id arxiv_https___arxiv_org_abs_2401_12604
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Pigeonhole Principles and Ramsey in TFNP
Jain, Siddhartha
Li, Jiawei
Robere, Robert
Xun, Zhiyang
Computational Complexity
We show that the TFNP problem RAMSEY is not black-box reducible to PIGEON, refuting a conjecture of Goldberg and Papadimitriou in the black-box setting. We prove this by giving reductions to RAMSEY from a new family of TFNP problems that correspond to generalized versions of the pigeonhole principle, and then proving that these generalized versions cannot be reduced to PIGEON. Formally, we define t-PPP as the class of total NP-search problems reducible to finding a t-collision in a mapping from (t-1)N+1 pigeons to N holes. These classes are closely related to multi-collision resistant hash functions in cryptography. We show that the generalized pigeonhole classes form a hierarchy as t increases, and also give a natural condition on the parameters t1, t2 that captures exactly when t1-PPP and t2-PPP collapse in the black-box setting. Finally, we prove other inclusion and separation results between these generalized PIGEON problems and other previously studied TFNP subclasses, such as PLS, PPA and PLC. Our separation results rely on new lower bounds in propositional proof complexity based on pseudoexpectation operators, which may be of independent interest.
title On Pigeonhole Principles and Ramsey in TFNP
topic Computational Complexity
url https://arxiv.org/abs/2401.12604