Off-line detection of a quasi-periodically recurring fragment in a numerical sequence

The paper considers a nontraditional–combinatorial–approach to solving the problem of a posteriori (off-line) noise-proof detection of a recurring fragment in a numerical sequence. Results are presented concerning the complexity, classification, and justification of algorithms for solving discrete extremal problems to which, within the combinatorial approach, some possible variants of this problem are reduced in the case when repetitions are quasiperiodic and the noise is additive.