This function returns true if and only if P is an equation or set of equations, each of which are of the form  where  is a name that is not a constant, and  is an algebraic expression that does not contain .

The names  are intended to define the coordinate space, and the expressions  are the corresponding coordinate values.

Objects of type point differ from objects of type Point in the (now deprecated) student package in that the coordinates are defined by names rather than by position in a list.