Two examples of Wilf-collapse

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چکیده

Two permutation classes, the X-class and subpermutations of increasing oscillation are shown to exhibit an exponential Wilf-collapse. This means that number distinct enumerations principal subclasses each these classes grows much more slowly than class itself whereas a priori, based only on symmetries class, there is no reason expect this. The underlying cause collapse in both cases ability apply some form local symmetry which, combined with greedy algorithm for detecting patterns yields

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ژورنال

عنوان ژورنال: Discrete Mathematics & Theoretical Computer Science

سال: 2021

ISSN: ['1365-8050', '1462-7264']

DOI: https://doi.org/10.46298/dmtcs.5986