Sum-of-squares optimization
A sum-of-squares optimization program is an optimization problem with a linear cost function and constraints that certain polynomials constructed from the decision variables should be sums of squares. When the maximum degree of the polynomials involved is fixed, sum-of-squares optimization is also known as the Lasserre hierarchy of semidefinite programming relaxations.
Source: Wikipedia — Sum-of-squares optimization (CC BY-SA 4.0)