The Exploits of Chevalier Dupin the introduction by Ellery Queen, and the non-fiction piece on Dupin by Harrison. "The Exploits of Chevalier Dupin" contains the following tales: The Exploits of Chevalier Dupin The Exploits of Chevalier Dupin is a collection of detective short stories by author Michael Harrison. It was released in 1968 by Mycroft & Moran in an edition of 1,917 copies. The stories are pastiches of the C. Auguste Dupin stories of Edgar Allan Poe. The stories were first published in Ellery Queen's Mystery Magazine. There is an expanded UK edition by a different publisher which adds a further five stories This appeared
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