- Russell’s paradox (Wikipedia)
In mathematical logic, Russell’s paradox (also known as Russell’s antinomy) is a set-theoretic paradox published by the British philosopher and mathematician Bertrand Russell in 1901. Russell’s paradox shows that every set theory that contains an unrestricted comprehension principle leads to contradictions. The paradox had already been discovered independently in 1899 by the German mathematician Ernst Zermelo. However, Zermelo did not publish the idea, which remained known only to David Hilbert, Edmund Husserl, and other academics at the University of Göttingen. At the end of the 1890s, Georg Cantor – considered the founder of modern set theory – had already realized that his theory would lead to a contradiction, as he told Hilbert and Richard Dedekind by letter.
- Ghana (Wikipedia)
Ghana, officially the Republic of Ghana, is a country in West Africa. It lies adjacent to the Gulf of Guinea and the Atlantic Ocean to the south, sharing a border with Ivory Coast in the west, Burkina Faso in the north, and Togo in the east. Ghana covers an area of 239,567 km^2 (92,497 sq mi), spanning diverse biomes that range from coastal savannas to tropical rainforests. With nearly 35 million inhabitants, Ghana is the second-most populous country in West Africa. The capital and largest city is Accra; other significant cities include Kumasi, Tamale, and Sekondi-Takoradi.
