Michael Harrison (writer) Michael Harrison (writer) Michael Harrison (25 April 1907 – 13 September 1991) was the pen name of English detective fiction and fantasy author Maurice Desmond Rohan. Michael Harrison was born in Milton, Kent, England, on 25 April 1907. He attended the University of London and served briefly in the British Military Intelligence during World War II. He married Marie-Yvonne Aubertin. Harrison published seventeen novels between 1934 and 1954 when he turned to writing detective fiction. He wrote pastiches of Conan Doyle's Sherlock Holmes and Poe's C. Auguste Dupin and was a noted Sherlock Holmes scholar. His most successful work, "In
Dupin cyclide of Dupin cyclides is invariant under the larger group of all Lie sphere transformations; any two Dupin cyclides are Lie-equivalent. They form (in some sense) the simplest class of Lie-invariant surfaces after the spheres, and are therefore particularly significant in Lie sphere geometry. The definition also means that a Dupin cyclide is the envelope of the one-parameter family of spheres tangent to three given mutually tangent spheres. It follows that it is tangent to infinitely many Soddy's hexlet configurations of spheres. A further special property of a cyclide is: An elliptic cyclide can be represented parametrically by the following formulas