__Corner Point OR Vertex:__

A point of a solution region where two of its boundary lines intersect is called a *corner point* or *vertex* of the solution region.

__Problem Constraint:__

In a certain problem from everyday life each linear inequality concerning the problem is called the *problem constraint*.

__Non – Negative Constraint OR Decision Variables:__

The variables used in the system of linear inequalities relating to the problems of everyday life are non–negative and are called *non–negative constraints* or *decision variables*.

__Feasible Region:__

The solution region of an inequality restricted to the first quadrant is called the *feasible region*. In the case both and are always non–negative, i.e. , .

__Feasible Solution:__

Each point of the feasible region is called the *feasible solution* of the system of linear inequalities.

__Feasible Solution Set:__

A set consisting of all the feasible solutions of the system of linear inequalities is called *feasible solution set*.

__Convex Region:__

If the line segment joining any two point of a certain region lies entirely within the region, then such a region is called the *convex region* as shown in the figure.