Christian Kramp

Christian Kramp (1760 to 1826) was a French mathematician from Strasbourg who trained and practised as a physician before turning to mathematics. He worked mainly on factorials and was the first to use the notation n! for the product of the whole numbers from n down to one, which he introduced in his Elements d'arithmetique universelle of 1808. He explained that constant use of the idea in combinatorial analysis made a short notation necessary, and he accepted the name factorial proposed by his friend Louis Arbogast. He also worked on a generalised factorial function for non-integers, independently of James Stirling and Vandermonde. Kramp became professor of mathematics at Strasbourg in 1809 and was elected to the French Academy of Sciences in 1817. A scaled complex error function that he studied is now better known as the Faddeeva function.