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 indicatrix Dupin indicatrix In differential geometry, the Dupin indicatrix is a method for characterising the local shape of a surface. Draw a plane parallel to the tangent plane and a small distance away from it. Consider the intersection of the surface with this plane. The shape of the intersection is related to the Gaussian curvature. The Dupin indicatrix is the result of the limiting process as the plane approaches the tangent plane. The indicatrix was invented by Charles Dupin. For elliptical points where the Gaussian curvature is positive the intersection will either be empty or form a closed curve. In the