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On the Gröbner complexity of matrices

In this paper we show that if for an integer matrix A the universal Gröbner basis of the associated toric ideal I A coincides with the Graver basis of A , then the Gröbner complexity u ( A ) and the Graver complexity g ( A ) of its higher Lawrence liftings agree, too. In fact, if the universal Gröbn...

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Bibliographic Details
Published in:Journal of pure and applied algebra 2009-08, Vol.213 (8), p.1558-1563
Main Authors: Hemmecke, Raymond, Nairn, Kristen A.
Format: Article
Language:English
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Summary:In this paper we show that if for an integer matrix A the universal Gröbner basis of the associated toric ideal I A coincides with the Graver basis of A , then the Gröbner complexity u ( A ) and the Graver complexity g ( A ) of its higher Lawrence liftings agree, too. In fact, if the universal Gröbner basis of I A coincides with the Graver basis of A , then also the more general complexities u ( A , B ) and g ( A , B ) agree for arbitrary B . We conclude that for the matrices A 3 × 3 and A 3 × 4 , defining the 3×3 and 3×4 transportation problems, we have u ( A 3 × 3 ) = g ( A 3 × 3 ) = 9 and u ( A 3 × 4 ) = g ( A 3 × 4 ) ≥ 27 . Moreover, we prove that u ( A a , b ) = g ( A a , b ) = 2 ( a + b ) / gcd ( a , b ) for positive integers a , b and A a , b = ( 1 1 1 1 0 a b a + b ) .
ISSN:0022-4049
1873-1376
DOI:10.1016/j.jpaa.2008.11.044