Lower bounds on pure dynamic programming for connectivity problems on graphs of bounded path-width

Fuente: arXiv
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Main Authors: Kluk, Kacper, Nederlof, Jesper
Format: Preprint
Published: 2025
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author Kluk, Kacper
Nederlof, Jesper
author_facet Kluk, Kacper
Nederlof, Jesper
contents We give unconditional parameterized complexity lower bounds on pure dynamic programming algorithms - as modeled by tropical circuits - for connectivity problems such as the Traveling Salesperson Problem. Our lower bounds are higher than the currently fastest algorithms that rely on algebra and give evidence that these algebraic aspects are unavoidable for competitive worst case running times. Specifically, we study input graphs with a small width parameter such as treewidth and pathwidth and show that for any $k$ there exists a graph $G$ of pathwidth at most $k$ and $k^{O(1)}$ vertices such that any tropical circuit calculating the optimal value of a Traveling Salesperson round tour uses at least $2^{Ω(k \log \log k)}$ gates. We establish this result by linking tropical circuit complexity to the nondeterministic communication complexity of specific compatibility matrices. These matrices encode whether two partial solutions combine into a full solution, and Raz and Spieker [Combinatorica 1995] previously proved a lower bound for this complexity measure.
format Preprint
id arxiv_https___arxiv_org_abs_2512_23121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Lower bounds on pure dynamic programming for connectivity problems on graphs of bounded path-width
Kluk, Kacper
Nederlof, Jesper
Computational Complexity
Data Structures and Algorithms
We give unconditional parameterized complexity lower bounds on pure dynamic programming algorithms - as modeled by tropical circuits - for connectivity problems such as the Traveling Salesperson Problem. Our lower bounds are higher than the currently fastest algorithms that rely on algebra and give evidence that these algebraic aspects are unavoidable for competitive worst case running times. Specifically, we study input graphs with a small width parameter such as treewidth and pathwidth and show that for any $k$ there exists a graph $G$ of pathwidth at most $k$ and $k^{O(1)}$ vertices such that any tropical circuit calculating the optimal value of a Traveling Salesperson round tour uses at least $2^{Ω(k \log \log k)}$ gates. We establish this result by linking tropical circuit complexity to the nondeterministic communication complexity of specific compatibility matrices. These matrices encode whether two partial solutions combine into a full solution, and Raz and Spieker [Combinatorica 1995] previously proved a lower bound for this complexity measure.
title Lower bounds on pure dynamic programming for connectivity problems on graphs of bounded path-width
topic Computational Complexity
Data Structures and Algorithms
url https://arxiv.org/abs/2512.23121