When is a gap function good for error bounds?

In this paper we survey some important classes of gap function for variational inequalities and also some recently introduced gap functions for generalized variational inequalities. A new gap function is proposed for generalized variational inequalities and error bound is developed. Error bounds are also developed for some particular classes of gap functions. In fact a … Read more

On Traveling Salesman Games with Asymmetric Costs

We consider cooperative traveling salesman games with non-negative asymmetric costs satisfying the triangle inequality. We construct a stable cost allocation with budget balance guarantee equal to the Held-Karp integrality gap for the asymmetric traveling salesman problem, using the parsimonious property and a previously unknown connection to linear production games. We also show that our techniques … Read more

Error Forgetting of Bregman Iteration

This short article analyzes an interesting property of the Bregman iterative procedure, which is equivalent to the augmented Lagrangian method after a change of variable, for minimizing a convex piece-wise linear function J(x) subject to linear constraints Ax=b. The procedure obtains its solution by solving a sequence of unconstrained subproblems of minimizing J(x)+1/2||Ax-b^k||^2, where b^k … Read more

Do You Trust Derivatives or Differences?

We analyze the relationship between the noise level of a function and the accuracy and reliability of derivatives and difference estimates. We derive and empirically validate measures of quality for both derivatives and difference estimates. Using these measures, we quantify the accuracy of derivatives and differences in terms of the noise level of the function. … Read more