Journal of Global Optimization
Global optimality conditions and optimization methods for quadratic integer programming problems
Journal of Global Optimization
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We consider the maximization $$\gamma = \max\{x^{T}\!Ax : x\in \{-1, 1\}^n\}$$ for a given symmetric $$A\in\mathcal{R}^{n\times n}$$ . It was shown recently, using properties of zonotopes and hyperplane arrangements, that in the special case that A has a small rank, so that A = VV T where $$V\in\mathcal{R}^{n\times m}$$ with m n, then there exists a polynomial time algorithm (polynomial in n for a given m) to solve the problem $$\max\{x^TV V^Tx : x\in \{-1, 1\}^n\}$$ . In this paper, we use this result, as well as a spectral decomposition of A to obtain a sequence of non-increasing upper bounds on 驴 with no constraints on the rank of A. We also give easily computable necessary and sufficient conditions for the absence of a gap between the solution and its upper bound. Finally, we incorporate the semidefinite relaxation upper bound into our scheme and give an illustrative example.