On October, 30 Skoltech professor Mikhail Gelfand gave a lecture on infinities in mathematics in the Center of Modern Culture “Smena” (Kazan). Professor talked about several counterintuitive features of infinite numbers. Particularly, he discussed the paradox of equality of number of rational and natural numbers. He also introduced an idea of infinite sets and proved that the number of real numbers cannot be calculated. The full text of press release is available here.