## Variable neighborhood search

The variable neighborhood search strategy involves iteratively exploring increasingly larger neighborhoods for a given local optimum until an improvement is located, after which the search in those neighborhoods is repeated. The strategy is motivated by three principles: 1) a local minimum for a neighborhood structure may not be a local minimum for a different neighborhood structure, 2) a global minimum is a local minimum for all possible neighborhood structures, and 3) the local minima are relatively close to the global minima for many classes of problems.