Researchers propose a hierarchy of semidefinite relaxations for polynomial optimization problems (POP) on the nonnegative orthant.
POP on a semialgebraic set in the nonnegative orthant can be converted to an equivalent form by squaring each variable, allowing for easier computations.
The proposed hierarchy is based on extending Pólya's Positivstellensatz by Dickinson-Povh, introducing even symmetry and factor width concepts.
A key feature of the new hierarchy is the ability to choose the maximal matrix size of each semidefinite relaxation arbitrarily.
The sequence of values obtained by the hierarchy converges to the optimal value of the original POP at a rate of O(ε^(-c)), provided the semialgebraic set has a nonempty interior.
The method is applied to tasks such as robustness certification of multi-layer neural networks and computation of positive maximal singular values.
Compared to the Moment-SOS hierarchy, the proposed method offers better bounds and significantly faster computation times, running several hundred times faster.