A note on eigenvalue distribution of constraint-preconditioned symmetric saddle point matrices

where A is symmetric positive definite (SPD), C is symmetric semi-positive definite, and B is of full rank. System of the form (1) arises in a variety of scientific and engineering applications, such as constrained optimization, least squares. We refer the reader to [1] for a more detailed list of applications and numerical solution techniques of (1). Recently, drawing on previous works: [2, 3], Bergamaschi [4] discussed two inexact constraint preconditioners as follows: