We consider Hammerstein equations of the form y(i)=f(t)+(hk(t,s)g(s,y(s))ds, te[a,b], J a and present a new method for solving them numerically. The method is a collocation method applied not to the equation in its original form, but rather to an equivalent equation for z(t):= g(t,y(t)). The desired approximation to y is then obtained by use of the (exact) equation y(t)=f(t) + fh k(t,s)z(s)ds, ...

We study the theory of best approximation in tensor product and the direct sum of some lattice normed spacesX_{i}. We introduce quasi tensor product space anddiscuss about the relation between tensor product space and thisnew space which we denote it by X boxtimesY. We investigate best approximation in direct sum of lattice normed spaces by elements which are not necessarily downwardor upward a...

in this paper, using the best proximity theorems for an extensionof brosowski's theorem. we obtain other results on farthest points. finally, wedene the concept of e- farthest points. we shall prove interesting relationshipbetween the -best approximation and the e-farthest points in normed linearspaces (x; ||.||). if z in w is a e-farthest point from an x in x, then z is also a-best ...

We prove the approximation ratio 8/5 for the metric {s, t}-path-TSP problem, and more generally for shortest connected T -joins. The algorithm that achieves this ratio is the simple “Best of Many” version of Christofides’ algorithm (1976), suggested by An, Kleinberg and Shmoys (2012), which consists in determining the best Christofides {s, t}-tour out of those constructed from a family F>0 of t...

Given a vertex-weighted connected graphG = (V,E), the maximum weight internal spanning tree (MwIST for short) problem asks for a spanning tree T of G such that the total weight of the internal vertices in T is maximized. The unweighted variant, denoted as MIST, is NPhard and APX-hard, and the currently best approximation algorithm has a proven performance ratio 13/17. The currently best approxi...

We prove the approximation ratio 8/5 for the metric {s, t}-path-TSP problem, and more generally for shortest connected T -joins. The algorithm that achieves this ratio is the simple “Best of Many” version of Christofides’ algorithm (1976), suggested by An, Kleinberg and Shmoys (2012), which consists in determining the best Christofides {s, t}-tour out of those constructed from a family F>0 of t...

Linear programming relaxations have been used extensively in designing approximation algorithms for optimization problems. For vertex cover, linear programming and a thresholding technique gives a 2-approximate solution, rivaling the best known performance ratio. For a generalization of vertex cover we call vc t , in which we seek to cover t edges, this technique may not yield a feasible soluti...