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arXiv · 1708.03654

Multi de Bruijn Sequences

Glenn Tesler
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Abstract

We generalize the notion of a de Bruijn sequence to a "multi de Bruijn sequence": a cyclic or linear sequence that contains every k-mer over an alphabet of size q exactly m times. For example, over the binary alphabet {0,1}, the cyclic sequence (00010111) and the linear sequence 000101110 each contain two instances of each 2-mer 00,01,10,11. We derive formulas for the number of such sequences. The formulas and derivation generalize classical de Bruijn sequences (the case m=1). We also determine the number of multisets of aperiodic cyclic sequences containing every k-mer exactly m times; for example, the pair of cyclic sequences (00011)(011) contains two instances of each 2-mer listed above. This uses an extension of the Burrows-Wheeler Transform due to Mantaci et al, and generalizes a result by Higgins for the case m=1.

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Glenn Tesler. 2017-08-11. Multi de Bruijn Sequences. https://doi.org/10.4310/joc.2017.v8.n3.a3

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