Аннотация:Things can be large or small, and their size (the length or the volume or the weight or so on) can be measured by a number. Besides, things can be simple or complex, and their complexity can also be measured by a number. I do not know to whom we are indebted for measuring sizes by numbers. It was Andrei Kolmogorov who proposed to measure the complexity of a thing by a natural number (i.e., a non-negative integer), and he developed the rudiments of the theory.
Preparation of this paper was supported in part by the Institute of New Technologies at Moscow.