Hadamard Difference Sets in Nonabelian 2-Groups with High Exponent

Authors

James A. Davis, University of RichmondFollow
Joel E. Iiams

DOI

10.1006/jabr.1997.7197

Abstract

Nontrivial difference sets in groups of order a power of 2 are part of the family of difference sets called Hadamard difference sets. In the abelian case, a group of order 2^{2t + 2} has a difference set if and only if the exponent of the group is less than or equal to 2^{t + 2}. In a previous work (R. A. Liebler and K. W. Smith, in “Coding Theory, Design Theory, Group Theory: Proc. of the Marshall Hall Conf.,” Wiley, New York, 1992), the authors constructed a difference set in a nonabelian group of order 64 and exponent 32. This paper generalizes that result to show that there is a difference set in a nonabelian group of order 2^{4t + 2} with exponent 2^{3t + 2}. Thus a nonabelian 2-group G with a Hadamard difference set can have exponent |G|^3/4 asymptotically. Previously the highest known exponent of a nonabelian 2-group with a Hadamard difference set was |G|^1/2 asymptotically. We use representation theory to prove that the group has a difference set.

Document Type

Article

Publication Date

1-1-1998

Publisher Statement

Copyright © 1998, Academic Press. This article first appeared in Journal of Algebra: 199:1 (1998), 62-87.

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Recommended Citation

Davis, James A., and Joel E. Iiams. "Hadamard Difference Sets in Nonabelian 2-Groups with High Exponent." Journal of Algebra 199, no. 1 (January 1, 1998): 62-87. doi:10.1006/jabr.1997.7197.