Fictional detectives Fictional detectives Fictional detectives are characters in detective fiction. These characters have long been a staple of detective mystery crime fiction, particularly in detective novels and short stories. Much of early detective fiction was written during the "Golden Age of Detective Fiction" (1920s-1930s). These detectives include amateurs, private investigators and professional policemen. They are often popularized as individual characters rather than parts of the fictional work in which they appear. Stories involving individual detectives are well-suited to dramatic presentation, resulting in many popular theatre, television, and movie characters. The first famous detective in fiction was Edgar Allan Poe's C. Auguste
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