C. Auguste Dupin features Dupin befriending a young boy named Edmund. The two solve mysteries together in Providence, Rhode Island. Dupin is revealed to be Edgar Allan Poe himself. Novelist George Egon Hatvary uses Dupin in his novel "The Murder of Edgar Allan Poe" (1997) as detective and narrator. Dupin travels to America to investigate the circumstances of Poe's mysterious death in 1849. In the novel, Dupin and Poe became friends when Poe stayed in Paris in 1829, and it was Poe who assisted Dupin in the three cases about which Poe wrote. Hatvary writes that Dupin resembles Poe, so much so that
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