Results 21 to 30 of about 570 (72)

Approximations of convex bodies by polytopes and by projections of spectrahedra [PDF]

open access: yes, 2012
We prove that for any compact set B in R^d and for any epsilon >0 there is a finite subset X of B of |X|=d^{O(1/epsilon^2)} points such that the maximum absolute value of any linear function ell: R^d --> R on X approximates the maximum absolute value of ...
Barvinok, Alexander
core   +1 more source

Exposed faces of semidefinitely representable sets

open access: yes, 2009
A linear matrix inequality (LMI) is a condition stating that a symmetric matrix whose entries are affine linear combinations of variables is positive semidefinite.
Netzer, Tim   +2 more
core   +1 more source

Support-based lower bounds for the positive semidefinite rank of a nonnegative matrix [PDF]

open access: yes, 2013
The positive semidefinite rank of a nonnegative $(m\times n)$-matrix~$S$ is the minimum number~$q$ such that there exist positive semidefinite $(q\times q)$-matrices $A_1,\dots,A_m$, $B_1,\dots,B_n$ such that $S(k,\ell) = \mbox{tr}(A_k^* B_\ell)$.
Dirk, Oliver Theis, Troy Lee
core  

Exploiting Group Symmetry in Truss Topology Optimization [PDF]

open access: yes
AMS classification: 90C22, 20Cxx, 70-08truss topology optimization;semidefinite programming;group ...
Bai, Y.Q.   +3 more
core   +1 more source

Improved bounds for the crossing numbers of K_m,n and K_n

open access: yes, 2004
It has been long--conjectured that the crossing number cr(K_m,n) of the complete bipartite graph K_m,n equals the Zarankiewicz Number Z(m,n):= floor((m-1)/2) floor(m/2) floor((n-1)/2) floor(n/2). Another long--standing conjecture states that the crossing
de Klerk, E.   +4 more
core   +2 more sources

On Semidefinite Programming Relaxations of the Travelling Salesman Problem (Replaced by DP 2008-96) [PDF]

open access: yes
AMS classification: 90C22, 20Cxx, 70-08traveling salesman problem;semidefinite programming;quadratic as- signment ...
Klerk, E. de   +2 more
core   +1 more source

On Semidefinite Programming Relaxations of Association Schemes With Application to Combinatorial Optimization Problems [PDF]

open access: yes
AMS classification: 90C22, 20Cxx, 70-08traveling salesman problem;maximum bisection;semidefinite programming;association ...
Klerk, E. de, Pasechnik, D.V.
core   +1 more source

Deciding polyhedrality of spectrahedra

open access: yes, 2015
Spectrahedra are linear sections of the cone of positive semidefinite matrices that, as convex bodies, generalize the class of polyhedra. In this paper we investigate the problem of recognizing when a spectrahedron is polyhedral.
Bhardwaj, Avinash   +2 more
core   +1 more source

On the Lovasz O-number of Almost Regular Graphs With Application to Erdos-Renyi Graphs [PDF]

open access: yes
AMS classifications: 05C69; 90C35; 90C22;Erdos-Renyi graph;stability number;Lovasz O-number;Schrijver O-number;C*-algebra;semidefinite ...
Klerk, E. de   +3 more
core   +1 more source

Exploiting Group Symmetry in Semidefinite Programming Relaxations of the Quadratic Assignment Problem [PDF]

open access: yes
We consider semidefinite programming relaxations of the quadratic assignment problem, and show how to exploit group symmetry in the problem data. Thus we are able to compute the best known lower bounds for several instances of quadratic assignment ...
Klerk, E. de, Sotirov, R.
core   +1 more source

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