**Christian Kramp** was a French mathematician who worked on analysis and combinatorics. He introduced the factorial notation.

- It has been a free city, a part of France and a part of Germany but in 1760, when Kramp was born there, it had been part of France for over 60 years and had enjoyed a long period of peace and prosperity.
- With both French and German spoken in the city, it was natural that Kramp was brought up to speak and write in both languages.
- It is clear from this work on mortality tables that Kramp was intent on applying mathematical techniques in his medical research.
- In 1795 France annexed the Rhineland region in which Kramp was carrying out his medical work and after this he decided to give up his work as a medical doctor and was appointed as a teacher in Cologne at the École Centrale of the Département of the Ruhr.
- The following years saw Kramp embrace mathematics more and more seriously.
- The influence of the French Revolution is seen on the title page since the author is given as "citizen Kramp" and it was "printed in the 7th year of the Republic".
- He followed this with the mathematical textbooks "Éléments d'arithmétique" Ⓣ(Elements of arithmetic) (Cologne-Paris, 1801), where again on the title page the author is given as "citizen Kramp" and the date is given as the 9th year of the Republic, and Éléments de géométrie Ⓣ(Elements of geometry) (Cologne, 1806), where now the author is C Kramp and there is no dating by year of the Republic.
- Kramp was appointed professor of mathematics at Strasbourg, the town of his birth, in 1809.
- Kramp was friendly with, and learnt much mathematics from, Carl Friedrich Hindenburg.
- This was important both in influencing Kramp to undertake some important work in combinatorics, the topic for which Hindenburg is most famed, and also for giving Kramp important outlets for his mathematical contributions in the various journals that Hindenburg published.
- As Bessel, Legendre and Gauss did, Kramp worked on the generalised factorial or γ function which applied to non-integers.
- Kramp sent his work on factorials of non-integers to Bessel who was influenced by it.
- Kramp did not use the term 'factorial' in his early work on this topic, which was around 1798, but rather the term 'faculty'.
- Kramp went further than simple factorials, however, in his article "Mémoire sur les facultés numériques" Ⓣ(Memoir on numerical faculties) published in Gergonne's Annales de Mathématiques in 1812.
- Kramp was elected to the geometry section of the Académie des Sciences in 1817.
- Many letters written by Kramp survive and these show that he was a man with a great deal of confidence in his own abilities.

Born 8 July 1760, Strasbourg, France. Died 13 May 1826, Strasbourg, France.

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**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive