Fruit (slang) fruit" (and rarely "old tin of fruit") to the 1920s in Britain possibly deriving from the phrase "fruit of the womb". In the United States, however, both "fruit" and "fruitcake" are seen as negative with fruitcake likely originating from "nutty as a fruitcake" (a crazy person). A costermonger was a street seller of fruit and vegetables. The term, which derived from the words "costard" (a type of apple) and "monger", i.e. "seller", came to be particularly associated with the "barrow boys" of London who would sell their produce from a wheelbarrow or wheeled market stall. Costermongers have existed in London
History of type theory History of type theory The type theory was initially created to avoid paradoxes in a variety of formal logics and rewrite systems. Later, type theory referred to a class of formal systems, some of which can serve as alternatives to naive set theory as a foundation for all mathematics. It has been tied to formal mathematics since "Principia Mathematica" to today's proof assistants. In a letter to Gottlob Frege (1902) Russell announced his discovery of the paradox in Frege's Begriffsschrift. Frege promptly responded, acknowledging the problem and proposing a solution in a technical discussion of "levels". To quote Frege: Incidentally,