Pareto improvement
= Pareto improvement
{c}
{title2=$u_i(a')\ge u_i(a)\ \forall i,\quad u_j(a')>u_j(a)\ \text{for some }j$}
A feasible change weakly increasing every participant's <utility> and strictly increasing at least one. An assignment is <Pareto optimal> exactly when no <Pareto improvement> exists. This comparison permits coordinated changes by several participants; it is different from a profitable <unilateral deviation> used to test a <Nash equilibrium>.