• Title/Summary/Keyword: Bruhat order

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GENERALIZED ALTERNATING SIGN MATRICES AND SIGNED PERMUTATION MATRICES

  • Brualdi, Richard A.;Kim, Hwa Kyung
    • Journal of the Korean Mathematical Society
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    • v.58 no.4
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    • pp.921-948
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    • 2021
  • We continue the investigations in [6] extending the Bruhat order on n × n alternating sign matrices to our more general setting. We show that the resulting partially ordered set is a graded lattice with a well-define rank function. Many illustrative examples are given.

GAUSS SUMS FOR U(2n + 1,$q^2$)

  • Kim, Dae-San
    • Journal of the Korean Mathematical Society
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    • v.34 no.4
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    • pp.871-894
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    • 1997
  • For a lifted nontrivial additive character $\lambda'$ and a multiplicative character $\chi$ of the finite field with $q^2$ elements, the 'Gauss' sums $\Sigma\lambda'$(tr $\omega$) over $\omega$ $\in$ SU(2n + 1, $q^2$) and $\Sigma\chi$(det $\omega$)$\lambda'$(tr $\omega$) over $\omega$ $\in$ U(2n + 1, $q^2$) are considered. We show that the first sum is a polynomial in q with coefficients involving certain new exponential sums and that the second one is a polynomial in q with coefficients involving powers of the usual twisted Kloosterman sums and the average (over all multiplicative characters of order dividing q-1) of the usual Gauss sums. As a consequence we can determine certain 'generalized Kloosterman sum over nonsingular Hermitian matrices' which were previously determined by J. H. Hodges only in the case that one of the two arguments is zero.

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