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 Dupin cyclide In mathematics, a Dupin cyclide or cyclide of Dupin is any geometric inversion of a standard torus, cylinder or double cone. In particular, these latter are themselves examples of Dupin cyclides. They were discovered by (and named after) Charles Dupin in his 1803 dissertation under Gaspard Monge. The key property of a Dupin cyclide is that it is a channel surface (envelope of a one-parameter family of spheres) in two different ways. This property means that Dupin cyclides are natural objects in Lie sphere geometry. Dupin cyclides are often simply known as "cyclides", but the latter term is