Lecture
This lecture covers the definition of functions from R^n to R, emphasizing the correspondence between numbers and the graph of the function. It explains how the deficiency of the image of a function is determined by the graph and the formula used to define real numbers. The lecture also delves into the concept of a boruce function and the whole level of deficiency. Examples are provided to illustrate these concepts, including the definition of the deficiency and the hemisphere. The lecture concludes with a detailed analysis of the deficiency per value and its implications on the graph of the function.