  In a recent paper, Hauenstein, Sturmfels, and the second author discovered a
conjectural bijection between critical points of the likelihood function on the
complex variety of matrices of rank r and critical points on the complex
variety of matrices of co-rank r-1. In this paper, we prove that conjecture for
rectangular matrices and for symmetric matrices, as well as a variant for
skew-symmetric matrices. To appear in International Mathematics Research
Notices.
