For such models, economists often use two-dimensional graphs instead of functions.
In a two-dimensional graph, two of the thermodynamic quantities may be shown on the horizontal and vertical axes.
This is the ordinary two-dimensional Cartesian graph studied in school algebra.
Usually it shows a two-dimensional graph of one or more electrical potential differences (vertical axis).
Expositions of economic reasoning often use two-dimensional graphs to illustrate theoretical relationships.
Such isolines are useful for representing more than two dimensions (or quantities) on two-dimensional graphs.
As a result, the small world model tends to a random graph rather than a two-dimensional graph as the shortcut probability is increased.
A two-dimensional graph is the graph of a function of one variable f(x).
Since the composite is considered a single good only for purposes of the model, analysis can be made on a two-dimensional graph.
The term also refers to the horizontal axis (typically x-axis) of any two-dimensional graph.