The Wolfram Language uses a large number of original algorithms to provide automatic systemwide support for inequalities and inequality constraints. Whereas equations can often be solved in terms of numbers, even representing solution sets for inequalities is only made possible by the Wolfram Language's symbolic capabilities.

Less (<)  ▪  Greater (>)  ▪  LessEqual (<=)  ▪  GreaterEqual (>=)  ▪  Equal (==)  ▪  Unequal (!=)  ▪  Between  ▪  ...

Boole — convert from inequalities to 0, 1 values

Piecewise — general piecewise function

FindInstance — search for particular solutions to inequalities

Reduce — reduce systems of inequalities to explicit nested form

FunctionDomain — find inequalities that describe the domain of a function

FunctionRange — find inequalities that describe the range of a function

Integrate, NIntegrate — integrate over regions defined by inequalities

RegionPlot, RegionPlot3D — plot regions defined by inequalities

FindMinimum, NMinimize, Minimize, ... — optimization over regions »

RegionFunction — option for constraining 2D or 3D plots to a region

PolyhedronData — find inequalities corresponding to named polyhedra

LogicalExpand — expand out composite inequalities

PiecewiseExpand — expand out piecewise functions