Corner Point OR Vertex:
A point of a solution region where two of its boundary lines intersect is called a corner point or the vertex of the solution region.
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.
The solution region of an inequality restricted to the first quadrant is called the feasible region. In this case both and are always non–negative, i.e. , .
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 the feasible solution set.
If the line segment joining any two points of a certain region lies entirely within the region, then such a region is called the convex region, as shown in the figure.