C. Auguste Dupin C. Auguste Dupin "Le Chevalier" C. Auguste Dupin is a fictional character created by Edgar Allan Poe. Dupin made his first appearance in Poe's "The Murders in the Rue Morgue" (1841), widely considered the first detective fiction story. He reappears in "The Mystery of Marie Rogêt" (1842) and "The Purloined Letter" (1844). Dupin is not a professional detective and his motivations for solving the mysteries change throughout the three stories. Using what Poe termed "ratiocination", Dupin combines his considerable intellect with creative imagination, even putting himself in the mind of the criminal. His talents are strong enough that he appears
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