- 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.
- Grover Cleveland (allthetropes.org)
Grover Cleveland (born Stephen Grover Cleveland) was the only American president to hold two non-consecutive terms, as the 22nd and 24th president (1885–89, 1893–97). Benjamin Harrison was the 23rd president, winning a bizarre race in 1888 in which Cleveland won the popular vote but Harrison prevailed in the Electoral College. Cleveland was also the second American president to get married while in office, and the only one to marry in the White House itself. He was also the only Democratic president in a period (1869-1913) of Republican executive dominance.