

Usually, this constant is represented as 1.0 or 100%. In a ternary plot, the proportions of the three variables "a", "b", and "c" must sum to some constant, "K". In game theory, it is often called a "simplex plot". In population genetics, it is often called a de Finetti diagram. It is used in petrology, mineralogy, metallurgy, and other physical sciences to show the compositions of systems composed of three species.

It graphically depicts the ratios of the three variables as positions in an equilateral triangle. A ternary plot, ternary graph, triangle plot, simplex plot, or de Finetti diagram is a barycentric plot on three variables which sum to a constant.
