On the existence of Pareto solutions for polynomial vector optimization problems

Abstract: We are interested in the existence of Pareto solutions to the vector optimization problem $$\text{Min}{\,\mathbb{R}^m+} {f(x) \,|\, x\in \mathbb{R}^n},$$ where $f\colon\mathbb{R}^n\to \mathbb{R}^m$ is a polynomial map. By using the {\em tangency variety} of $f$ we first construct a semi-algebraic set of dimension at most $m - 1$ containing the set of Pareto values of the problem. Then we establish connections between the Palais--Smale conditions, $M$-tameness, and properness for the map $f$. Based on these results, we provide some sufficient conditions for the existence of Pareto solutions of the problem. We also introduce a generic class of polynomial vector optimization problems having at least one Pareto solution.