Using Petal-Decompositions to Build a Low Stretch Spanning Tree
We prove that any weighted graph $G=(V,E,w)$ with $n$ points and $m$ edges has a spanning tree $T$ such that $\sum_{\{u,v\}\in E}\frac{d_T(u,v)}{w(u,v)}=O(m\log n\log\log n)$. Moreover, such a tree can be found in time $O(m\log n\log\log n)$. Our result is ...
Steiner Point Removal with Distortion $O(\log {k})$ using the Relaxed-Voronoi Algorithm
In the Steiner point removal problem, we are given a weighted graph $G=(V,E)$ and a set of terminals $K\subset V$ of size $k$. The objective is to find a minor $M$ of $G$ with only the terminals as its vertex set, such that distances between the terminals ...
Approximation via Correlation Decay When Strong Spatial Mixing Fails
Approximate counting via correlation decay is the core algorithmic technique used in the sharp delineation of the computational phase transition that arises in the approximation of the partition function of antiferromagnetic 2-spin models. Previous analyses ...
On the Distortion of Locality Sensitive Hashing
Given a notion of pairwise similarity between objects, locality sensitive hashing (LSH) aims to construct a hash function family over the universe of objects such that the probability two objects hash to the same value is their similarity. LSH is a ...
Efficient Approximations for the Online Dispersion Problem
The dispersion problem has been widely studied in computational geometry and facility location and is closely related to the packing problem. The goal is to locate $n$ points (e.g., facilities or persons) in a $k$-dimensional polytope, so that they are far ...
Minimum Bisection Is Fixed-Parameter Tractable
In the classic Minimum Bisection problem we are given as input an undirected graph $G$ and an integer $k$. The task is to determine whether there is a partition of $V(G)$ into two parts $A$ and $B$ such that $||A|-|B|| \leq 1$ and there are at most $k$ ...
Special Section on the Fifty-Seventh Annual IEEE Symposium on Foundations of Computer Science (FOCS 2016)
This special section comprises eleven fully refereed papers whose extended abstracts were presented at the 57th Annual IEEE Symposium on Foundations of Computer Science (FOCS 2016) in New Brunswick, New Jersey, October 9--11, 2016. The unrefereed ...
Local Search Yields a PTAS for $k$-Means in Doubling Metrics
The most well-known and ubiquitous clustering problem encountered in nearly every branch of science is undoubtedly $k$-means: given a set of data points and a parameter $k$, select $k$ centers and partition the data points into $k$ clusters around these ...
Truly Subcubic Algorithms for Language Edit Distance and RNA Folding via Fast Bounded-Difference Min-Plus Product
It is a major open problem whether the $(\min,+)$-product of two $n\times n$ matrices has a truly subcubic (i.e., $O(n^{3-\varepsilon})$ for $\varepsilon>0$) time algorithm; in particular, since it is equivalent to the famous all-pairs-shortest-paths ...
The Constant Inapproximability of the Parameterized Dominating Set Problem
A set $D$ of vertices of a graph $G$ is a dominating set if every vertex of $G$ is contained in $D$ or adjacent to some vertex of $D$. The number of vertices in a smallest dominating set of $G$ is denoted by $\gamma(G)$. We prove that, under the assumption ${...
An Algorithm for Komlós Conjecture Matching Banaszczyk's Bound
We consider the problem of finding a low discrepancy coloring for sparse set systems where each element lies in at most $t$ sets. We give an efficient algorithm that finds a coloring with discrepancy $O((t \log n)^{1/2})$, matching the best known ...
Interleaved Group Products
Let $G$ be the special linear group ${SL}(2,q)$. We show that if $(a_1,\ldots,a_t)$ and $(b_1,\ldots,b_t)$ are sampled uniformly from large subsets $A$ and $B$ of $G^t$, then their interleaved product $a_1 b_1 a_2 b_2 \cdots a_t b_t$ is nearly uniform over $...
Convergence of MCMC and Loopy BP in the Tree Uniqueness Region for the Hard-Core Model
We study the hard-core (gas) model defined on independent sets of an input graph where the independent sets are weighted by a parameter (aka fugacity) $\lambda>0$. For constant $\Delta$, the previous work of Weitz [Proceedings of STOC, 2006, pp. 140--149] ...
Local Search Yields Approximation Schemes for $k$-Means and $k$-Median in Euclidean and Minor-Free Metrics
We give the first polynomial-time approximation schemes (PTASs) for the following problems: (1) uniform facility location in edge-weighted planar graphs; (2) $k$-median and $k$-means in edge-weighted planar graphs; and (3) $k$-means in Euclidean space of ...
Depth Reduction for Composites
We show that every circuit with ${AND},{OR},{NOT}$, and ${MOD}_m$ gates, $m\in\mathbb{Z}^+$, of polynomial size and depth $d$ can be reduced to a depth-2, ${SYM}\circ{AND}$, circuit of size $2^{(\log n)^{O(d)}}$. This is an exponential size improvement ...
A Nearly Tight Sum-of-Squares Lower Bound for the Planted Clique Problem
We prove that with high probability over the choice of a random graph $G$ from the Erdös--Rényi distribution $G(n,1/2)$, the $n^{O(d)}$-time degree $d$ sum-of-squares (SOS) semidefinite programming relaxation for the clique problem will give a value of at ...
Linear Hashing Is Awesome
We consider the hash function $h(x) = ((ax+b)mod p)mod n$ where $a,b$ are chosen uniformly at random from $\{0,1,\ldots,p-1\}$. We prove that when we use $h(x)$ in hashing with chaining to insert $n$ elements into a table of size $n$ the expected length of ...
Robust Estimators in High-Dimensions Without the Computational Intractability
We study high-dimensional distribution learning in an agnostic setting where an adversary is allowed to arbitrarily corrupt an $\varepsilon$-fraction of the samples. Such questions have a rich history spanning statistics, machine learning, and theoretical ...