On some fine-grained questions in algorithms and complexity

VV Williams - Proceedings of the international congress of …, 2018 - World Scientific
In recent years, a new “fine-grained” theory of computational hardness has been developed,
based on “fine-grained reductions” that focus on exact running times for problems …

Monochromatic triangles, triangle listing and APSP

VV Williams, Y Xu - 2020 IEEE 61st Annual Symposium on …, 2020 - ieeexplore.ieee.org
All-Pairs Shortest Paths (APSP) is one of the most basic problems in graph algorithms.
Given an n-node directed or undirected graph with integer weights in {-nc,..., nc} and no …

An equivalence class for orthogonal vectors

L Chen, R Williams - Proceedings of the Thirtieth Annual ACM-SIAM …, 2019 - SIAM
Abstract The Orthogonal Vectors problem (OV) asks: given n vectors in {0, 1} O (log n), are
two of them orthogonal? OV is easily solved in O (n 2 log n) time, and it is a central problem …

Approximately counting and sampling small witnesses using a colorful decision oracle

H Dell, J Lapinskas, K Meeks - SIAM Journal on Computing, 2022 - SIAM
In this paper, we design efficient algorithms to approximately count the number of edges of a
given k-hypergraph, and to sample an approximately uniform random edge. The hypergraph …

The orthogonal vectors conjecture and non-uniform circuit lower bounds

R Williams - 2024 IEEE 65th Annual Symposium on …, 2024 - ieeexplore.ieee.org
A line of work has shown how nontrivial uniform algorithms for analyzing circuits can be
used to derive non-uniform circuit lower bounds. We show how the non-existence of …

Induced cycles and paths are harder than you think

M Dalirrooyfard, VV Williams - 2022 IEEE 63rd Annual …, 2022 - ieeexplore.ieee.org
The goal of the paper is to give fine-grained hardness results for the Subgraph Isomorphism
(SI) problem for fixed size induced patterns H, based on the k-Clique hypothesis that the …

Listing cliques from smaller cliques

M Dalirrooyfard, S Mathialagan, VV Williams… - arXiv preprint arXiv …, 2023 - arxiv.org
We study finding and listing $ k $-cliques in a graph, for constant $ k\geq 3$, a fundamental
problem of both theoretical and practical importance. Our main contribution is a new output …

Truly subcubic min-plus product for less structured matrices, with applications

VV Williams, Y Xu - Proceedings of the Fourteenth Annual ACM-SIAM …, 2020 - SIAM
The All-Pairs Shortest Paths (APSP) problem is one of the most basic problems in computer
science. The fastest known algorithms for APSP in n-node graphs run in n 3− o (1) time, and …

Fast unbalanced optimal transport on a tree

R Sato, M Yamada, H Kashima - Advances in neural …, 2020 - proceedings.neurips.cc
This study examines the time complexities of the unbalanced optimal transport problems
from an algorithmic perspective for the first time. We reveal which problems in unbalanced …

SETH says: Weak Fréchet distance is faster, but only if it is continuous and in one dimension

K Buchin, T Ophelders, B Speckmann - … of the Thirtieth Annual ACM-SIAM …, 2019 - SIAM
We show by reduction from the Orthogonal Vectors problem that algorithms with strongly
subquadratic running time cannot approximate the Fréchet distance between curves better …