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The computation of Kostka Numbers and Littlewood-Richardson Coefficients is #P-complete

Hariharan Narayanan
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Abstract

Kostka numbers and Littlewood-Richardson coefficients play an essential role in the representation theory of the symmetric groups and the special linear groups. There has been a significant amount of interest in their computation. The issue of their computational complexity has been a question of folklore, but was asked explicitly by E. Rassart. We prove that the computation of either quantity is #P-complete. The reduction to computing Kostka numbers, is from the #P-complete problem of counting the number of 2 x k contingency tables having given row and column sums. The main ingredient in this reduction is a correspondence discovered by D. E. Knuth. The reduction to the problem of computing Littlewood-Richardson coefficients is from that of computing Kostka numbers.

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Hariharan Narayanan. 2005-01-12. The computation of Kostka Numbers and Littlewood-Richardson Coefficients is #P-complete. https://arxiv.org/abs/math/0501176

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