C. Auguste Dupin features Dupin befriending a young boy named Edmund. The two solve mysteries together in Providence, Rhode Island. Dupin is revealed to be Edgar Allan Poe himself. Novelist George Egon Hatvary uses Dupin in his novel "The Murder of Edgar Allan Poe" (1997) as detective and narrator. Dupin travels to America to investigate the circumstances of Poe's mysterious death in 1849. In the novel, Dupin and Poe became friends when Poe stayed in Paris in 1829, and it was Poe who assisted Dupin in the three cases about which Poe wrote. Hatvary writes that Dupin resembles Poe, so much so that
Dupin cyclide also used to refer to a more general class of quartic surfaces which are important in the theory of separation of variables for the Laplace equation in three dimensions. Dupin cyclides were investigated not only by Dupin, but also by A. Cayley und J.C. Maxwell. Today, Dupin cylides are used in computer-aided design (CAD), because cyclide patches have rational representations and are suitable for blending canal surfaces (cylinder, cones, tori, and others). There are several equivalent definitions of Dupin cyclides. In formula_1, they can be defined as the images under any inversion of tori, cylinders and double cones. This shows