A tour d'horizon of de Casteljau's work (Q6615384)

In this tribute to Paul de Casteljau, the author reflects on his life, and his numerous contributions to geometry and number theory.\N\NPaul de Casteljau joined Citroën in 1958 as a young mathematician, where he worked until his retirement and left a profound impact on the CAD community. In the first section, the author writes a short biography and gives a detailed account of de Casteljau's time at Citroën.\N\NIn the next two sections the author describes de Casteljau's contributions to geometry and number theory. The author makes brief descriptions and sketches some proofs, so the arguments are not easy to follow unless the reader is familiar with the notation and details of the theorems. As the author says, this account is not exhaustive but ``has been intended to whet the appetite of the interested reader.'' The author includes various sources and excerpts from letters to other researchers.\N\NBesides the well-known de Casteljau's algorithm, the author promotes lesser known contributions like his work on projective geometry, motivated by the interest of his brother Henri on the subject, or his study of quaternions as orthogonal frames of reference. In summary, this paper makes for an interesting read for those curious about the history of CAD, and the impact of mathematics on engineering and the car industry.