Hazel Perfect
Hazel Perfect (circa 1927 – 8 July 2015) was a British mathematician specialising in combinatorics. Contributions Perfect was known for inventing gammoids, for her work with Leon Mirsky on doubly stochastic matrices, for her three books Topics in Geometry, Topics in Algebra, and Independence Theory in Combinatorics, and for her work as a translator (from an earlier German translation) of Pavel Alexandrov's book An Introduction to the Theory of Groups (Hafner, 1959). The Perfect–Mirsky conjecture, named after Perfect and Leon Mirsky, concerns the region of the complex plane formed by the eigenvalues of doubly stochastic matrices. Perfect and Mirsky conjectured that for matrices this region is the union of regular polygons of up to sides, having the roots of unity of each degree up to as vertices. Perfect and Mirsky proved their conjecture for ; it was subsequently shown to be true for and false for , but remains open for larger values Education and career Perfect earned a master's degree through Westfield College (a constituent college for women in the University of London) in 1949, with a thesis on The Reduction of Matrices to Canonical Form. In the 1950s, Perfect was a lecturer at University College of Swansea; she