Approximation algorithms for some NP-hard problems of searching a vectors subsequence

Some NP-hard problems of searching a subsequence in a finite sequence of Euclidean vectors are studied. It is assumed that the desired subsequence has a fixed number of vectors which are mutually close under the criterion of minimum sum of squared distances. Moreover, there is an additional requirement that the difference between the numbers of any two consecutive vectors must lie between two given constants. Some effective 2-approximation algorithms for these problems are presented. Bibliogr. 11.