9 citations · 50 across the 22 of their papers we have counts for
23 papers
On solving integer bilevel optimization problems with a non-convex quadratic follower objective function using disjunctive cuts
Kübra Tanınmış, Elisabeth Gaar, Jon Lee +2
In this work, we study bilevel optimization problems where all variables are integer, all constraints and the leader objective function are linear, and the follower objective funct…
An semidefinite programming-based -constraint method for the bi-objective single-row facility layout problem
Christof Brandstetter, Elisabeth Gaar, Markus Sinnl
In this work, we introduce a multi-objective version of the well-known single-row facility layout problem (SRFLP). In the SRFLP, a set of one-dimensional facilities should be place…
A note on the maximal covering location problem with customer preference ordering
Elisabeth Gaar, Markus Sinnl
Recently a series of papers introduced and investigated the maximal covering location problem with customer preference ordering, a variant of the classical maximal covering locatio…
Investigating mixed-integer programming approaches for the --closest-center problem
Elisabeth Gaar, Sara Joosten, Markus Sinnl
In this work, we introduce and study the --closest-center problem (CCP), which generalizes the -second-center problem, a recently emerged variant of the classical -…
An exact approach for the multi-depot electric vehicle scheduling problem
Xenia Haslinger, Elisabeth Gaar, Sophie N. Parragh
The "avoid - shift - improve" framework and the European Clean Vehicles Directive set the path for improving the efficiency and ultimately decarbonizing the transport sector. While…
The exact subgraph hierarchy and its vertex-transitive variant for the stable set problem for Paley graphs
Elisabeth Gaar, Dunja Pucher
The stability number of a graph, defined as the cardinality of the largest set of pairwise non-adjacent vertices, is NP-hard to compute. The exact subgraph hierarchy (ESH) provides…
Strong SDP based bounds on the cutwidth of a graph
Elisabeth Gaar, Diane Puges, Angelika Wiegele
Given a linear ordering of the vertices of a graph, the cutwidth of a vertex with respect to this ordering is the number of edges from any vertex before (including ) to…
Exact solution approaches for the discrete -neighbor -center problem
Elisabeth Gaar, Markus Sinnl
The discrete -neighbor -center problem (d--CP) is an emerging variant of the classical -center problem which recently got attention in literature. In this problem, w…
On SOCP-based disjunctive cuts for solving a class of integer bilevel nonlinear programs
Elisabeth Gaar, Jon Lee, Ivana Ljubić +2
We study a class of integer bilevel programs with second-order cone constraints at the upper-level and a convex-quadratic objective function and linear constraints at the lower-lev…
Sum-of-Squares Certificates for Vizing's Conjecture via Determining Gröbner Bases
Elisabeth Gaar, Melanie Siebenhofer
The famous open Vizing conjecture claims that the domination number of the Cartesian product graph of two graphs and is at least the product of the domination numbers of $G…
SOCP-based disjunctive cuts for a class of integer nonlinear bilevel programs
Elisabeth Gaar, Jon Lee, Ivana Ljubić +2
We study a class of bilevel integer programs with second-order cone constraints at the upper level and a convex quadratic objective and linear constraints at the lower level. We de…
A scaleable projection-based branch-and-cut algorithm for the -center problem
Elisabeth Gaar, Markus Sinnl
The -center problem (pCP) is a fundamental problem in location science, where we are given customer demand points and possible facility locations, and we want to choose of t…
An SDP-Based Approach for Computing the Stability Number of a Graph
Elisabeth Gaar, Melanie Siebenhofer, Angelika Wiegele
Finding the stability number of a graph, i.e., the maximum number of vertices of which no two are adjacent, is a well known NP-hard combinatorial optimization problem. Since this p…
Experiments with graph convolutional networks for solving the vertex -center problem
Elisabeth Gaar, Markus Sinnl
In the last few years, graph convolutional networks (GCN) have become a popular research direction in the machine learning community to tackle NP-hard combinatorial optimization pr…
A Computational Study of Exact Subgraph Based SDP Bounds for Max-Cut, Stable Set and Coloring
Elisabeth Gaar, Franz Rendl
The "exact subgraph" approach was recently introduced as a hierarchical scheme to get increasingly tight semidefinite programming relaxations of several NP-hard graph optimization…
A characterization of graphs with regular distance- graphs
Elisabeth Gaar, Daniel Krenn
For non-negative integers~, we consider graphs in which every vertex has exactly vertices at distance~, i.e., graphs whose distance- graphs are -regular. We call su…
Towards a Computational Proof of Vizing's Conjecture using Semidefinite Programming and Sums-of-Squares
Elisabeth Gaar, Daniel Krenn, Susan Margulies +1
Vizing's conjecture (open since 1968) relates the product of the domination numbers of two graphs to the domination number of their Cartesian product graph. In this paper, we formu…
On different Versions of the Exact Subgraph Hierarchy for the Stable Set Problem
Elisabeth Gaar
Let be a graph with vertices and edges. One of several hierarchies towards the stability number of is the exact subgraph hierarchy (ESH). On the first level it comp…
On -Bend and Monotonic -Bend Edge Intersection Graphs of Paths on a Grid
Eranda Çela, Elisabeth Gaar
If a graph can be represented by means of paths on a grid, such that each vertex of corresponds to one path on the grid and two vertices of are adjacent if and only if…
Improving ADMMs for Solving Doubly Nonnegative Programs through Dual Factorization
Martina Cerulli, Marianna De Santis, Elisabeth Gaar +1
Alternating direction methods of multipliers (ADMMs) are popular approaches to handle large scale semidefinite programs that gained attention during the past decade. In this paper,…
Monotonic Representations of Outerplanar Graphs as Edge Intersection Graphs of Paths on a Grid
Eranda Cela, Elisabeth Gaar
In a representation of a graph as an edge intersection graph of paths on a grid (EPG) every vertex of is represented by a path on a grid and two paths share a grid edge iff…
A Bundle Approach for SDPs with Exact Subgraph Constraints
Elisabeth Gaar, Franz Rendl
The 'exact subgraph' approach was recently introduced as a hierarchical scheme to get increasingly tight semidefinite programming relaxations of several NP-hard graph optimization…
An Optimization-Based Sum-of-Squares Approach to Vizing's Conjecture
Elisabeth Gaar, Daniel Krenn, Susan Margulies +1
Vizing's conjecture (open since 1968) relates the sizes of dominating sets in two graphs to the size of a dominating set in their Cartesian product graph. In this paper, we formula…