Active constraint

Let be given a constrained optimization problem

maximize $f(x)$, $x\in\mathbf R^n$,

subject to $g_i(x)\leq0$, $i=1,\ldots,m$.

The $i$th constraint is said to be active (at a solution $y$) if $g_i(y)=0$.

See also Passive constraint. For a selection of references, see Mathematical programming.