 The name gamma function and the symbol were introduced by Adrien-Marie Legendre around 1811; Legendre also rewrote Euler's integral definition in its modern form.Although the symbol is an upper-case Greek gamma, there is no accepted standard for whether the function name should be written "gamma function" or "Gamma function" (some authors simply write "-function").The alternative "pi function" notation due to Gauss is sometimes encountered in older literature, but Legendre's notation is dominant in modern works.