We observe a curious property of dual versus primal-dual path-following interior-point methods when applied to unbounded linear or conic programming problems in dual form. While primal-dual methods can be viewed as implicitly following a central path to detect primal infeasibility and dual unboundedness, dual methods can sometimes implicitly move away from the analytic center of the set of infe...

The Finite Element Tearing and Interconnecting (FETI) methods were first introduced by Farhat and Roux [FMR94]. An important advance, making the rate of convergence of the iteration less sensitive to the number of unknowns of the local problems, was made by Farhat, Mandel, and Roux a few years later [FMR94]. For a detailed introduction, see [FR94] and we also refer to our own papers for many ad...

A production function highly concave in inputs will have a dual profit function less convex in prices. Even large variations in prices will cause little variation in input usage and output, resulting in poor profit function estimates. This is demonstrated using Monte Carlo simulation with various curvatures and error structures.

The cooccurrence of HIV and unintended pregnancy has prompted a body of work on dual protection, the simultaneous protection against HIV and unintended pregnancy. This study examines dual protection and dual methods as a risk-reduction strategy for women living with HIV. Data are from a cross-sectional sample of HIV-positive women attended in Specialized STI/AIDS Public Health Service Clinics i...