Gentleman detective English country house. This archetype of British detective contrasts with the more "hardboiled" counterpart in American crime fiction. Gentlemen detectives appeared early in modern detective fiction, which began in the late 19th century. C. Auguste Dupin, created by Edgar Allan Poe, is widely considered to be the first fictional detective in English literature. He appeared in three short stories written in the 1840s: "The Murders in the Rue Morgue" (1841), "The Mystery of Marie Rogêt" (1842) and "The Purloined Letter" (1844). Poe created Dupin before the word "detective" had been coined, but began many common elements of detective fiction: Dupin
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