Application of graphic expression in the proof of set theoretical statements

Mathematical statements are proved using verbal reasoning. An addition to the traditional way of presenting evidence is proposed. The progress of the proof is presented graphically. There are almost no verbal explanations. The student can visually trace the development of the proof in time (consecutive steps to obtain the desired result) and in space (branching that arise in the course of the proof, and which require a separate study). This way of presenting evidence has been developed and used for many years in teaching the Discrete Mathematics course to students of computer specialties of the Siberian State Automobile and Highway University.