Title
A Note on the Augmented Hessian When the Reduced Hessian is Semidefinite
Abstract
Certain matrix relationships play an important role in optimality conditions and algorithms for nonlinear and semidefinite programming. Let H be an n × n symmetric matrix, A an m × n matrix, and Z a basis for the null space of A. (In a typical optimization context, H is the Hessian of a smooth function and A is the Jacobian of a set of constraints.) When the reduced Hessian ZTHZ is positive definite, augmented Lagrangian methods rely on the known existence of a finite $\bar\rho\ge 0$ such that, for all $\rho \bar\rho$, the augmented Hessian $H + \rho \ATA $ is positive definite. In this note we analyze the case when ZTHZ is positive semidefinite, i.e., singularity is allowed, and show that the situation is more complicated. In particular, we give a simple necessary and sufficient condition for the existence of a finite $\bar\rho$ so that $H + \rho \ATA$ is positive semidefinite for $\rho \ge \bar\rho$. A corollary of our result is that if H is nonsingular and indefinite while ZTHZ is positive semidefinite and singular, no such $\bar\rho$ exists.
Year
DOI
Venue
2000
10.1137/S1052623499351791
SIAM Journal on Optimization
Keywords
Field
DocType
important role,augmented hessian,known existence,augmented lagrangian method,n matrix,reduced hessian zthz,reduced hessian,semidefinite programming,certain matrix relationship,n symmetric matrix,positive semidefinite,augmented lagrangian methods,inertia
Hessian equation,Mathematical optimization,Jacobian matrix and determinant,Matrix (mathematics),Positive-definite matrix,Hessian matrix,Symmetric matrix,Invertible matrix,Semidefinite programming,Mathematics
Journal
Volume
Issue
ISSN
11
1
1052-6234
Citations 
PageRank 
References 
11
1.48
3
Authors
2
Name
Order
Citations
PageRank
Kurt M. Anstreicher163386.40
Margaret H. Wright21233182.31