Infinity symbol Infinity symbol The infinity symbol (sometimes called the lemniscate) is a mathematical symbol representing the concept of infinity. The shape of a sideways figure eight has a long pedigree; for instance, it appears in the cross of Saint Boniface, wrapped around the bars of a Latin cross. However, John Wallis is credited with introducing the infinity symbol with its mathematical meaning in 1655, in his "De sectionibus conicis". Wallis did not explain his choice of this symbol, but it has been conjectured to be a variant form of a Roman numeral for 1,000 (originally CIƆ, also CƆ), which was sometimes
Prime (symbol) to subscripts – "x"′ generally means something related to or derived from "x". For example, if a point is represented by the Cartesian coordinates , then that point rotated, translated or reflected might be represented as . The prime symbol is not related to prime numbers. Usually, the meaning of "x"′ is defined when it is first used, but sometimes its meaning is assumed to be understood: The prime is said to "decorate" the letter to which it applies. The same convention is adopted in functional programming, particularly in Haskell. In geometry, geography and astronomy, prime and double prime are