C. Auguste Dupin Dupin" is at the center of Matthew Pearl's novel "The Poe Shadow" (2006). Dupin makes an appearance, alongside Poe himself, in the novel "Edgar Allan Poe on Mars" (2007) by Jean-Marc Lofficier & Randy Lofficier. In "Murder in the Madhouse" (1935), the first of Jonathan Latimer's series of screwball crime novels starring detective William Crane, Crane presents himself in the sanitarium as C. Auguste Dupin. The story contains more oblique references in the form of stylistic elements (offstage murders, Crane's theories of deduction) that suggest Poe had an influence on Latimer's writing. Dupin is the hero of "Les ogres de
Dupin cyclide that the class of Dupin cyclides is invariant under Möbius (or conformal) transformations. In complex space formula_2 these three latter varieties can be mapped to one another by inversion, so Dupin cyclides can be defined as inversions of the torus (or the cylinder, or the double cone). Since a standard torus is the orbit of a point under a two dimensional abelian subgroup of the Möbius group, it follows that the cyclides also are, and this provides a second way to define them. A third property which characterizes Dupin cyclides is that their curvature lines are all circles (possibly through