The Traveling Salesman
Assume we have all interpoint distances between n cities, giving a search space of
(n - 1)! different tours. What is a good notion of neighborhood?
The most obvious notion is to consider two tours as being close if they differ in
just a few edges. They can't differ in just one edge, so we will
consider differences that can be obtained by removing two edges of s and then
putting in two other edges. Here's an example of a local move:
