Gamma-Lines

To a large extent, the history of mathematics and the study of solutions of f(x)=a=const for functions f(x) of one real or complex variable are intertwined. Therefore, it is surprising that we know little about solutions of u(x,y)=A=const for functions of two real variables. These two solutions, called level of sets, are important in physics, biology, and economics, as they map appropriate processes described by the function u(x,y) for given parameters (x,y). This text explores the a-points concept along with the Gamma-lines concept and generalizes the notion of levels of sets and a-points. The general methods proposed are useful to both physicists and engineers.