Charles R. Johnson Charles R. Johnson is Class of 1961 Professor of Mathematics at the College of William and Mary, Virginia. He is the recognized expert in the interplay between linear algebra and combinatorics, as well as many parts of matrix analysis. He is coauthorof Matrix Analysis (Cambridge, 2012), Topics in Matrix Analysis (Cambridge, 2010), both with Roger Horn, and Totally Nonnegative Matrices (2011, with Shaun Fallat). Read More Read Less