C. Auguste Dupin Vanished Treasure" (May 1965) and "The Fires in the Rue St. Honoré" (January 1967). This collection was subsequently published in England by Tom Stacey in 1972 as "Murder in the Rue Royale and Further Exploits of the Chevalier Dupin" and included a further five stories written since the original publication. Dupin had considerable impact on the Agatha Christie character Hercule Poirot, first introduced in "The Mysterious Affair at Styles" (1920). Later in the fictional detective's life, he writes a book on Edgar Allan Poe in the novel "Third Girl" (1966). "The Man Who Was Poe", a juvenile novel by Avi,
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