activity
20102022
most citedDeterministic polynomial-time approximation algorithms for partition functions and graph polynomials

115 citations · 203 across the 24 of their papers we have counts for

collaborators

27 papers

cs.DS2022★ 2 cited

Approximate counting using Taylor's theorem: a survey

Viresh Patel, Guus Regts

In this article we consider certain well-known polynomials associated with graphs including the independence polynomial and the chromatic polynomial. These polynomials count certai…

math.CO2022

Hamilton Cycles in Dense Regular Digraphs and Oriented Graphs

Allan Lo, Viresh Patel, Mehmet Akif Yıldız

We prove that for every there exists such that every regular oriented graph on vertices and degree at least $(1/4 + \varepsilon)n…

math.CO2021

Path decompositions of random directed graphs

Alberto Espuny Díaz, Viresh Patel, Fabian Stroh

We consider the problem of decomposing the edges of a directed graph into as few paths as possible. There is a natural lower bound for the number of paths needed in an edge decompo…

math.CO2021

Improved bounds for zeros of the chromatic polynomial on bounded degree graphs

Maurizio Moreschi, Viresh Patel, Guus Regts +1

We prove that for any graph of maximum degree at most , the zeros of its chromatic polynomial (in ) lie outside the disk of radius centered at…

math.CO2021★ 8 cited

Sampling from the low temperature Potts model through a Markov chain on flows

Jeroen Huijben, Viresh Patel, Guus Regts

In this paper we consider the algorithmic problem of sampling from the Potts model and computing its partition function at low temperatures. Instead of directly working with spin c…

math.CO2020

Switch-based Markov Chains for Sampling Hamiltonian Cycles in Dense Graphs

Pieter Kleer, Viresh Patel, Fabian Stroh

We consider the irreducibility of switch-based Markov chains for the approximate uniform sampling of Hamiltonian cycles in a given undirected dense graph on vertices. As our ma…

math.CO2020

A polynomial-time algorithm to determine (almost) Hamiltonicity of dense regular graphs

Viresh Patel, Fabian Stroh

We give a polynomial-time algorithm for detecting very long cycles in dense regular graphs. Specifically, we show that, given , there exists a such that the fo…

cs.CC2020

Lee-Yang zeros and the complexity of the ferromagnetic Ising model on bounded-degree graphs

Pjotr Buys, Andreas Galanis, Viresh Patel +1

We study the computational complexity of approximating the partition function of the ferromagnetic Ising model with the external field parameter on the unit circle in the compl…

math.CO2019

Structure and colour in triangle-free graphs

N. R. Aravind, Stijn Cambie, Wouter Cames van Batenburg +3

Motivated by a recent conjecture of the first author, we prove that every properly coloured triangle-free graph of chromatic number contains a rainbow independent set of size $…

cs.DS2019★ 3 cited

Statistical physics approaches to Unique Games

Matthew Coulson, Ewan Davies, Alexandra Kolla +2

We show how two techniques from statistical physics can be adapted to solve a variant of the notorious Unique Games problem, potentially opening new avenues towards the Unique Game…

math.CO2019★ 4 cited

Decomposing tournaments into paths

Allan Lo, Viresh Patel, Jozef Skokan +1

We consider a generalisation of Kelly's conjecture which is due to Alspach, Mason, and Pullman from 1976. Kelly's conjecture states that every regular tournament has an edge decomp…

math.CO2018★ 3 cited

On zero-free regions for the anti-ferromagnetic Potts model on bounded-degree graphs

Ferenc Bencs, Ewan Davies, Viresh Patel +1

For a graph , , and a complex number the partition function of the univariate Potts model is defined as \[ {\bf Z}(G;k,w):=\sum_{ϕ:V\to [k]}\prod_{\su…

cs.DS2017

Computing the number of induced copies of a fixed graph in a bounded degree graph

Viresh Patel, Guus Regts

In this paper we show that for any graph of order and any graph of order and maximum degree one can compute the number of subsets of that induces a g…

math.CO2016

Discrepancy and large dense monochromatic subsets

Ross Kang, Viresh Patel, Guus Regts

Erdős and Pach (1983) introduced the natural degree-based generalisations of Ramsey numbers, where instead of seeking large monochromatic cliques in a -edge coloured complete gr…

math.CO2016★ 115 cited

Deterministic polynomial-time approximation algorithms for partition functions and graph polynomials

Viresh Patel, Guus Regts

In this paper we show a new way of constructing deterministic polynomial-time approximation algorithms for computing complex-valued evaluations of a large class of graph polynomial…

math.CO2015

Excluding hooks and their complements

Krzysztof Choromanski, Dvir Falik, Anita Liebenau +2

The celebrated Erdos-Hajnal conjecture states that for every -vertex undirected graph there exists $\eps(H)>0$ such that every graph that does not contain as an indu…

math.CO2015

Hamilton cycles in sparse robustly expanding digraphs

Allan Lo, Viresh Patel

The notion of robust expansion has played a central role in the solution of several conjectures involving the packing of Hamilton cycles in graphs and directed graphs. These and ot…

math.CO2014★ 1 cited

On a Ramsey-type problem of Erdős and Pach

Ross J. Kang, Eoin Long, Viresh Patel +1

In this paper we show that there exists a constant such that for any graph on vertices either or its complement has an induced subgraph on ver…

cs.DS2014

Parameterized TSP: Beating the Average

Gregory Gutin, Viresh Patel

In the Travelling Salesman Problem (TSP), we are given a complete graph together with an integer weighting on the edges of , and we are asked to find a Hamilton cycl…

cs.CC2014★ 2 cited

Finding Shortest Paths between Graph Colourings

Matthew Johnson, Dieter Kratsch, Stefan Kratsch +2

The -colouring reconfiguration problem asks whether, for a given graph , two proper -colourings and of , and a positive integer , there exists a sequence…

math.CO2014★ 4 cited

A precise threshold for quasi-Ramsey numbers

Ross J. Kang, János Pach, Viresh Patel +1

We consider a variation of Ramsey numbers introduced by Erdős and Pach (1983), where instead of seeking complete or independent sets we only seek a -homogeneous set, a vertex su…

cs.DS2014

A domination algorithm for -instances of the travelling salesman problem

Daniela Kühn, Deryk Osthus, Viresh Patel

We present an approximation algorithm for -instances of the travelling salesman problem which performs well with respect to combinatorial dominance. More precisely, we giv…

cs.DM2013

Mixing of the Glauber dynamics for the ferromagnetic Potts model

Magnus Bordewich, Catherine Greenhill, Viresh Patel

We present several results on the mixing time of the Glauber dynamics for sampling from the Gibbs distribution in the ferromagnetic Potts model. At a fixed temperature and interact…

math.CO2013★ 31 cited

Proof of a conjecture of Thomassen on Hamilton cycles in highly connected tournaments

Daniela Kühn, John Lapinskas, Deryk Osthus +1

A conjecture of Thomassen from 1982 states that for every k there is an f(k) so that every strongly f(k)-connected tournament contains k edge-disjoint Hamilton cycles. A classical…