Hercule Poirot and Frank Howel Evans' Monsieur Poiret, a retired Belgian police officer living in London. A more obvious influence on the early Poirot stories is that of Arthur Conan Doyle. In "An Autobiography", Christie states, "I was still writing in the Sherlock Holmes tradition – eccentric detective, stooge assistant, with a Lestrade-type Scotland Yard detective, Inspector Japp". For his part, Conan Doyle acknowledged basing his detective stories on the model of Edgar Allan Poe's C. Auguste Dupin and his anonymous narrator, and basing his character Sherlock Holmes on Joseph Bell, who in his use of "ratiocination" prefigured Poirot's reliance on his
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