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    Strong external difference families and classification of α-valuations

    Kreher, D.L. and Paterson, Maura B. and Stinson, D.R. (2025) Strong external difference families and classification of α-valuations. Journal of Combinatorial Designs , ISSN 1520-6610. (In Press)

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    Abstract

    One method of constructing (a2 + 1, 2, a, 1)-SEDFs (i.e., strong external difference families) in Za2+1 makes use of α-valuations of complete bipartite graphs Ka,a. We explore this approach and we provide a classification theorem which shows that all such α-valuations can be constructed recursively via a sequence of “blow-up” operations. We also enumerate all (a2 +1, 2, a, 1)-SEDFs in Za2+1 for a ≤ 14 and we show that all these SEDFs are equivalent to α-valuations via affine transformations. Whether this holds for all a > 14 as well is an interesting open problem. We also study SEDFs in dihedral groups, where we show that two known constructions are equivalent.

    Metadata

    Item Type: Article
    School: Birkbeck Faculties and Schools > Faculty of Science > School of Computing and Mathematical Sciences
    Depositing User: Maura Paterson
    Date Deposited: 23 Apr 2025 13:36
    Last Modified: 29 Apr 2025 16:19
    URI: https://eprints.bbk.ac.uk/id/eprint/55413

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