Theory

Fri, Oct 304 papers

arXiv

Algorithm finds largest graph pairings in near-quadratic time

For general graphs, the algorithm’s running-time bound grew nearly as the square of the number of points when finding the largest set of non-overlapping links.For general graphs, the algorithm’s running-time bound grew nearly as the square of the number of points when finding the largest set of non-overlapping links.

A light blue network contains distinct black pairs, surrounded by scattered dark blue-green circles, gray strips, and a smaller branching network.
Preprint: method
arXiv

The Tight Competitive Ratio of Greedy for Online Steiner Forest

Iman Gholami, Ilya Hajiaghayi, MohammadTaghi Hajiaghayi et al.

The online Steiner Forest problem is a fundamental network design problem in which terminal pairs arrive one at a time and an algorithm must irrevocably purchase edges…The online Steiner Forest problem is a fundamental network design problem in which terminal pairs arrive one at a time and an algorithm must irrevocably purchase edges connecting each pair.

Preprint: theory
arXiv

Four-Coloring Planar Graphs in Linear Time

Yuta Inoue, Ken-ichi Kawarabayashi, Atsuyuki Miyashita et al.

The famous Four Color Theorem (4CT) states that any planar graph can be colored with four colors, but how do we find a 4-coloring?The famous Four Color Theorem (4CT) states that any planar graph can be colored with four colors, but how do we find a 4-coloring? In our previous paper [FOCS'26], we presented a simple combinatorial algorithm to 4-color planar…

Preprint: method
arXiv

Standard graph searches face a worst-case speed limit

Standard graph methods could not guarantee search times growing more slowly than the dataset’s size, even with arbitrarily loose approximations.Standard graph methods could not guarantee search times growing more slowly than the dataset’s size, even with arbitrarily loose approximations.

A light blue network has a short path through dark blue-green junctions, beside a dense gray network with a long winding path.
Preprint: theory

Wed, Oct 284 papers

arXiv

UPP^(cc) is Not Closed Under Intersection

Mark Bun, Mandar Juvekar

The sign rank of a ± 1-valued matrix A is the minimum rank of a real matrix that agrees with A entrywise in sign.The sign rank of a ± 1-valued matrix A is the minimum rank of a real matrix that agrees with A entrywise in sign. For every sufficiently large d, we give an explicit matrix A with 2^(Θ(d^2)) rows and columns and sign rank Θ(d)…

Preprint: theory
arXiv

Impossibility of No-Regret in Multi-Agent Bidding

Zongjun Yang, Rachitesh Kumar, Christian Kroer

We consider T repeated second-price auctions across n pacing bidders with i.i.d. item arrivals, and show that it is computationally impossible for all bidders to achieve…We consider T repeated second-price auctions across n pacing bidders with i.i.d. item arrivals, and show that it is computationally impossible for all bidders to achieve no-regret simultaneously while satisfying their respective…

Preprint: theory
arXiv

An Unconditional Space-Approximation Lower Bound for Semi-Streaming Matching

Yang P. Liu, Kheeran Naidu, Hoai-An Nguyen et al.

We prove the first unconditional lower bound tradeoff between the number of passes and the approximation factor of maximum matchings in the semi-streaming model.We prove the first unconditional lower bound tradeoff between the number of passes and the approximation factor of maximum matchings in the semi-streaming model.

An RS-graph with parameters t=4, and r=3.
Preprint: theory
arXiv

When Multiple-Unicast Feasibility Is Equivalent to Single-Sink Routability

Sirui Liu, Zongpeng Li, Baochun Li

In communication networks, network coding allows intermediate nodes to combine messages, achieving transmission rates unattainable by routing alone in many multicast…In communication networks, network coding allows intermediate nodes to combine messages, achieving transmission rates unattainable by routing alone in many multicast settings.

Preprint: theory

Tue, Oct 273 papers

arXiv

From Linear to Polylogarithmic: Dynamic Submodular Maximization over Matroids

Kiarash Banihashem, Samira Goudarzi, MohammadTaghi Hajiaghayi et al.

We study the problem of submodular maximization under a matroid constraint. In this problem, there is a monotone submodular function f: 2^N → R⁺ and a matroid $M(N, I)$…We study the problem of submodular maximization under a matroid constraint. In this problem, there is a monotone submodular function f: 2^N → R⁺ and a matroid $M(N, I)$, accessible via value and independence oracles and the goal…

Preprint: method
arXiv

A math proof resolves a 2009 network flow conjecture

The preprint proves that pairwise arc-disjoint directed paths from all senders to each receiver ensure unit flows between matched pairs in an undirected network.The preprint proves that pairwise arc-disjoint directed paths from all senders to each receiver ensure unit flows between matched pairs in an undirected network.

A network of light blue and dark blue-green routes surrounds a continuous black path, with circular endpoints and a small fan of separate gray branches.
Preprint: theory
arXiv

Optimal Worst-Case Open Addressing: Braided Cuckoo Hashing

Andrew Krapivin, William Kuszmaul

In this paper, we introduce braided cuckoo hashing, an open-addressed hash table that supports load factor up to 1 - ε (for some parameter ε ∈ (0, 1)), while supporting…In this paper, we introduce braided cuckoo hashing, an open-addressed hash table that supports load factor up to 1 - ε (for some parameter ε ∈ (0, 1)), while supporting queries, insertions, and deletions in worst-case time O(log…

Preprint: method

Mon, Oct 266 papers

arXiv

Learning Positive Linear Combinations of ReLUs in Fully Polynomial Time

Ilias Diakonikolas, Jelena Diakonikolas, Puqian Wang et al.

We study the fundamental problem of PAC learning positive linear combinations of k arbitrary ReLU activations on R^d with respect to the Gaussian distribution, in L₂…We study the fundamental problem of PAC learning positive linear combinations of k arbitrary ReLU activations on R^d with respect to the Gaussian distribution, in L₂ loss.

Preprint: theory
arXiv

Structure and Exact Certification of Nonnegative Tensor Decompositions

Haoming Wang, Ming Yuan

We study the structure and exact certification of nonnegative tensor decompositions supplied through rational factor matrices.We study the structure and exact certification of nonnegative tensor decompositions supplied through rational factor matrices. Every failure of minimality or essential uniqueness contains an irreducible positive exchange between p…

Preprint: method
arXiv

A Linear Lower Bound for Convex Body Chasing in Every ℓ_p Norm

Nicolas Christianson

We establish an Ω(d) lower bound on the competitive ratio of convex body chasing in R^d with ℓ_p movement costs for any p ∈ [1, ∞).We establish an Ω(d) lower bound on the competitive ratio of convex body chasing in R^d with ℓ_p movement costs for any p ∈ [1, ∞). Previously, the best known lower bound for general p was Ω(max{√d, d^(1-1/p)}), established by…

Preprint: theory
arXiv

Combinatorial Minimum Cost Flow in Almost-Linear Time on Dense Graphs

Bernhard Haeupler, Yonggang Jiang, Thatchaphol Saranurak

We give a combinatorial algorithm that computes an exact minimum-cost flow in n^(2+o(1)) time. This is the first combinatorial improvement since Goldberg-Tarjan [GT87]…We give a combinatorial algorithm that computes an exact minimum-cost flow in n^(2+o(1)) time. This is the first combinatorial improvement since Goldberg-Tarjan [GT87], and is almost optimal in dense graphs.

Preprint: method
arXiv

Pareto-optimal Scheduling with Predictions

Ziyad Benomar, Vianney Perchet

We study preemptive single-machine scheduling with predictions, where a prediction of the order of the jobs (or of their sizes) is available, and the objective is to…We study preemptive single-machine scheduling with predictions, where a prediction of the order of the jobs (or of their sizes) is available, and the objective is to minimize the total completion time.

Preprint: theory
arXiv

Proof settles communication limit for graph connectivity

A mathematical proof establishes an optimal lower bound on nondeterministic communication for graph connectivity, resolving a problem that remained open for decades.A mathematical proof establishes an optimal lower bound on nondeterministic communication for graph connectivity, resolving a problem that remained open for decades.

A connected light blue network with black branches sits beside a large cluster of dark blue-green rectangles and a smaller gray cluster.
Preprint: theory

Fri, Oct 232 papers

arXiv

No Perfect Randomized Composition

Alexander Meiburg

Does computing a composition of total Boolean functions require the product of the randomized query complexities of its factors? We give a negative answer.Does computing a composition of total Boolean functions require the product of the randomized query complexities of its factors? We give a negative answer.

Preprint: theory
arXiv

Pigeonhole Equal Subset Sum: Subexponential Algorithm, Tight Lower Bounds, and Average-Case Analysis

Deepak Bhati, Pranjal Dutta, Antoine Joux et al.

The Equal Subset Sum problem asks, given n positive integers bounded by M, to find two distinct non-empty subsets with the same sum.The Equal Subset Sum problem asks, given n positive integers bounded by M, to find two distinct non-empty subsets with the same sum. We study this problem in the regime M = 2^(o(n)), where the pigeonhole principle guarantees that…

Preprint: method

Thu, Oct 226 papers

arXiv

Algorithm solves simple stochastic games in quasipolynomial time

The mathematical method calculates approximate fixed points for nonexpanding mappings and shows that simple stochastic games can be solved in quasipolynomial time.The mathematical method calculates approximate fixed points for nonexpanding mappings and shows that simple stochastic games can be solved in quasipolynomial time.

A light blue maze surrounds tightly nested squares and a black dot, with a black path, scattered dark blue-green fragments, and loose gray squares.
Preprint: method
arXiv

Pfaffian Recognition is in coRP

Priyanshu Pant, Ranveer Singh

A graph is called Pfaffian if it admits a Pfaffian orientation. The Pfaffian recognition problem asks whether a given graph is Pfaffian.A graph is called Pfaffian if it admits a Pfaffian orientation. The Pfaffian recognition problem asks whether a given graph is Pfaffian. In 1989, Vazirani and Yannakakis showed that this problem is polynomial time equivalent to…

Preprint: theory
arXiv

Minimax Rates for imperfect Physics-Informed Regression

Nathan Doumèche

Physics-informed machine learning incorporates physical knowledge into data-driven models, often through a partial differential equation (PDE) that the target is assumed…Physics-informed machine learning incorporates physical knowledge into data-driven models, often through a partial differential equation (PDE) that the target is assumed to satisfy.

Preprint: theory
arXiv

Zero Knowledge for Free up to Linear Query Bounds: Quasilinear-Size Constant-Query Zero-Knowledge PCPs

Inhyuk Park, Chenglin Fan

We show that for all polynomials T and b, every relation in NTIME(T) has a binary PCP with O(1) non-adaptive queries, perfect completeness, soundness error 1/2 and length…We show that for all polynomials T and b, every relation in NTIME(T) has a binary PCP with O(1) non-adaptive queries, perfect completeness, soundness error 1/2 and length (T+b)·(log(T+b))^(O(1)), which is perfect zero knowledge…

Preprint: theory
arXiv

Fixed Sets and the Hardness of Computing Correlated Equilibria

Ioannis Anagnostides, Constantinos Daskalakis, Gabriele Farina et al.

We show that computing an approximate correlated equilibrium of a polytope game is PPAD-complete, and thus polynomial-time equivalent to finding a Nash equilibrium.We show that computing an approximate correlated equilibrium of a polytope game is PPAD-complete, and thus polynomial-time equivalent to finding a Nash equilibrium.

Preprint: theory
arXiv

Optimal Algorithms and Hardness for Max-Cut in Bounded Degree Graphs

Rares-Darius Buhai, Suprovat Ghoshal, Neng Huang et al.

We give a polynomial-time algorithm that achieves an α_GW + Ω(1/d)-approximation for Max 2-LIN(2) in weighted instances where each vertex appears in at most d…We give a polynomial-time algorithm that achieves an α_GW + Ω(1/d)-approximation for Max 2-LIN(2) in weighted instances where each vertex appears in at most d constraints.

Preprint: theory

Wed, Oct 218 papers

arXiv

Matrix Multiplication from Polynomial Packings: A Constructive and Elementary Proof of ω≤9/4

Rafael Pass

We give a self-contained constructive proof that the matrix multiplication exponent satisfies ω≤9/4. This bound was recently claimed by OpenAI~cite{original} through…We give a self-contained constructive proof that the matrix multiplication exponent satisfies ω≤9/4. This bound was recently claimed by OpenAI~cite{original} through non-constructive arguments in Strassen's asymptotic spectral…

Preprint: theory
arXiv

Two ReLU Layers is All You Need

Florestan Brunck, Christoph Hertrich, Kilian Ruess et al.

We prove that every ReLU network can be exactly simulated by a ReLU network with two hidden layers. We present two proofs: one that is based on fillings in homological…We prove that every ReLU network can be exactly simulated by a ReLU network with two hidden layers. We present two proofs: one that is based on fillings in homological algebra and a direct combinatorial proof.

Preprint: theory
arXiv

Birthday Estimators Are Uniformly Optimal for Renyi Entropy

Maciej Skórski

Collisions are a basic probe of unknown distributions, used for testing and for counting substructures in graphs, and they underlie R'enyi entropy, a fundamental measure…Collisions are a basic probe of unknown distributions, used for testing and for counting substructures in graphs, and they underlie R'enyi entropy, a fundamental measure of uncertainty with applications in cryptography, machine…

Preprint: theory
arXiv

Dynamic Distances Without Matrix Inverse

Jan van den Brand, Adam Karczmarz, Aryan Patel

We study the fully dynamic exact distance problem in unweighted directed graphs, where the graph undergoes edge insertions and deletions, and the distance between two…We study the fully dynamic exact distance problem in unweighted directed graphs, where the graph undergoes edge insertions and deletions, and the distance between two query vertices must be reported.

Preprint: method
arXiv

Exact Envy-Free Cake Cutting with Polynomial Expected Queries

Simon Mackenzie, Mashbat Suzuki

Envy-free cake cutting asks how to divide a resource so that no agent prefers another agent's share. Finding such a division with few queries about preferences has been a…Envy-free cake cutting asks how to divide a resource so that no agent prefers another agent's share. Finding such a division with few queries about preferences has been a longstanding challenge.

Preprint: method
arXiv

Racer: Hunting GPU Kernel Bugs with Symbolic Equivalence Checking

Tuan Truong Vu, Cheng Tan

GPU kernels are critical to the performance of today's AI services, yet the same operators are rewritten repeatedly: for each GPU generation, numeric format, serving…GPU kernels are critical to the performance of today's AI services, yet the same operators are rewritten repeatedly: for each GPU generation, numeric format, serving regime, and kernel language.

Preprint: system
arXiv

Certified Adaptive List Decoding for Error-Correcting Codes

Jaeho Hwang, Byung-Sun Won, Uiwon Hwang

Maximum-likelihood (ML) decoding of linear block codes is NP-hard, so neural decoders are evaluated by how closely they approach it.Maximum-likelihood (ML) decoding of linear block codes is NP-hard, so neural decoders are evaluated by how closely they approach it. We observe that proving a candidate optimal can be far easier than finding it, and build a…

Preprint: method
arXiv

Short Point Lists for CNFs and Stronger Constant-Depth Circuit Hardness

Xin Li, Yan Zhong

We give a short-description decomposition of bounded-width CNFs. For every fixed ε>0, every width-b CNF on m variables is an exact disjoint union of at most 2^(ε m)…We give a short-description decomposition of bounded-width CNFs. For every fixed ε>0, every width-b CNF on m variables is an exact disjoint union of at most 2^(ε m) width-b CNFs, each determined by 2^(O_ε(b))log(m+1) satisfying…

Preprint: theory

Tue, Oct 205 papers

arXiv

Tight Inapproximability for Generalized Circuits

Panagiotis Kanellopoulos, Themistoklis Melissourgos

Generalized circuits are a fundamental tool for establishing PPAD-hardness and membership of approximate equilibrium problems.Generalized circuits are a fundamental tool for establishing PPAD-hardness and membership of approximate equilibrium problems. Despite their importance, the complexity of finding approximate solutions has remained unresolved for a…

Preprint: theory
arXiv

Integer Programing: An Algorithm with Exponent Linear in the Dimension

Lin Chen, Yuchen Mao, Guochuan Zhang

We study integer programs in standard form min{c^Tx:Ax=b, lleqxlequ, xinZⁿ}, where AinZ^(d× n) and all entries of b,c,l,u are integers.We study integer programs in standard form min{c^Tx:Ax=b, lleqxlequ, xinZⁿ}, where AinZ^(d× n) and all entries of b,c,l,u are integers. Let N be an upper bound on the absolute values of the entries of A.

Preprint: method
arXiv

No Escape from the Quadratic Barrier: Adaptive Attacks on Linear ℓ₂ Sketches

Edith Cohen, Uri Stemmer

Linear sketches estimate properties of high-dimensional inputs from a fixed low-dimensional projection.Linear sketches estimate properties of high-dimensional inputs from a fixed low-dimensional projection. At constant accuracy, randomized Euclidean-norm sketches, notably the Johnson-Lindenstrauss transform, support exponentially…

Preprint: theory
arXiv

Computing faster with a full memory: Catalytic algorithms break time-space lower bounds

Adelmo Morrison Orozco, Nathan Sheffield, Ryan Williams

We show that adding "catalytic space" (which starts full and must have its original contents restored at the end of computation) provably speeds up time-and-space-bounded…We show that adding "catalytic space" (which starts full and must have its original contents restored at the end of computation) provably speeds up time-and-space-bounded computation.

Preprint: theory
arXiv

Undirected Network Coding and Faster External-Memory Integer Sorting

Baochun Li, Zongpeng Li, Sirui Liu

Network coding allows intermediate nodes to combine messages. Fractional routing instead splits each message among source-destination paths and forwards its parts without…Network coding allows intermediate nodes to combine messages. Fractional routing instead splits each message among source-destination paths and forwards its parts without combining different messages.

Preprint: method

Mon, Oct 19

arXiv

Unconditional Quantum PAC Learning Advantage in the Large Error Regime

Igor C. Oliveira

We establish an unconditional super-polynomial separation between quantum and classical PAC learning of Boolean functions under the uniform distribution in the large…We establish an unconditional super-polynomial separation between quantum and classical PAC learning of Boolean functions under the uniform distribution in the large error regime.

Preprint: theory