2.6. Functions of many variables (FMP) 2.6.1. Scope of FMP

The quantity z is called a function of two variables x and y on the set D , if each point of this set corresponds to one or several specific values ​​of z . The set of points D is called the domain of function definition.

Scope of function may be:

• the part of the plane bounded by a closed curve, and the points of this curve may or may not belong to the domain of definition;
• the whole plane;
• set of several parts of the plane.