Detective fiction underworld and undercover surveillance, rather than brilliance of imagination or intellect. Detective fiction in the English-speaking world is considered to have begun in 1841 with the publication of Poe's "The Murders in the Rue Morgue", featuring "the first fictional detective, the eccentric and brilliant C. Auguste Dupin". When the character first appeared, the word detective did not even exist. However, the character's name, "Dupin", originated from the English word dupe or deception. Poe devised a "plot formula that's been successful ever since, give or take a few shifting variables." Poe followed with further Auguste Dupin tales: "The Mystery of Marie
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