The art gallery problem is∃ ℝ-complete

M Abrahamsen, A Adamaszek, T Miltzow - ACM Journal of the ACM …, 2021 - dl.acm.org
Given a simple polygon P, we say that two points p, q∈ P see each other if the line segment
pq is contained in P. A set of points G⊆ P is said to guard the polygon P if every point p∈ P …

The graph crossing number and its variants: A survey

M Schaefer - The electronic journal of combinatorics, 2012 - combinatorics.org
The crossing number is a popular tool in graph drawing and visualization, but there is not
really just one crossing number; there is a large family of crossing number notions of which …

Training Fully Connected Neural Networks is -Complete

D Bertschinger, C Hertrich… - Advances in …, 2023 - proceedings.neurips.cc
We consider the algorithmic problem of finding the optimal weights and biases for a two-
layer fully connected neural network to fit a given set of data points, also known as empirical …

Fixed points, Nash equilibria, and the existential theory of the reals

M Schaefer, D Štefankovič - Theory of Computing Systems, 2017 - Springer
We introduce the complexity class∃ ℝ ∃R based on the existential theory of the reals. We
show that the definition of∃ ℝ ∃R is robust in the sense that even the fragment of the theory …

Parameterized analysis and crossing minimization problems

M Zehavi - Computer Science Review, 2022 - Elsevier
In this survey/introductory article, we first present the basics of the field of Parameterized
Complexity, made accessible to readers without background on the subject. Afterwards, we …

[CARTE][B] Crossing numbers of graphs

M Schaefer - 2018 - taylorfrancis.com
Crossing Numbers of Graphs is the first book devoted to the crossing number, an
increasingly popular object of study with surprising connections. The field has matured into a …

Training neural networks is ER-complete

M Abrahamsen, L Kleist… - Advances in Neural …, 2021 - proceedings.neurips.cc
Given a neural network, training data, and a threshold, finding weights for the neural network
such that the total error is below the threshold is known to be NP-hard. We determine the …

Smoothing the gap between NP and ER

J Erickson, I Van Der Hoog, T Miltzow - SIAM Journal on Computing, 2022 - SIAM
We study algorithmic problems that belong to the complexity class of the existential theory of
the reals (). A problem is-complete if it is as hard as the problem existential theory of the …

Sphere and dot product representations of graphs

RJ Kang, T Müller - Proceedings of the twenty-seventh annual …, 2011 - dl.acm.org
A graph G is a k-sphere graph if there are k-dimensional real vectors v1,..., vn such that ij∈
E (G) if and only if the distance between vi and vj is at most 1. A graph G is a k-dot product …

Framework for -Completeness of Two-Dimensional Packing Problems

M Abrahamsen, T Miltzow, N Seiferth - TheoretiCS, 2024 - theoretics.episciences.org
The aim in packing problems is to decide if a given set of pieces can be placed inside a
given container. A packing problem is defined by the types of pieces and containers to be …