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arXiv 1801.04852math.AGquant-ph
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边秩在张量积下不是乘法的

Border rank is not multiplicative under the tensor product

Matthias Christandl, Fulvio Gesmundo, Asger Kjærulff Jensen

摘要:

最近证明了张量秩在张量积下是严格次乘的,这里两个张量的张量积是一个张量,其阶是两个因子的阶之和.借助于边秩得到了必要的上界。边界秩本身是否可以是严格的次乘法,这是一个悬而未决的问题。我们对这个问题的回答是肯定的。为了做到这一点,我们在射影空间中构造了边界秩多次下降的线,并将此结果与之前的张量秩下降构造结合使用。我们的结果也意味着严格的次乘法仙人掌秩和边界仙人掌秩。

英文摘要:

It has recently been shown that the tensor rank can be strictly submultiplicative under the tensor product, where the tensor product of two tensors is a tensor whose order is the sum of the orders of the two factors. The necessary upper bounds were obtained with help of border rank. It was left open whether border rank itself can be strictly submultiplicative. We answer this question in the affirmative. In order to do so, we construct lines in projective space along which the border rank drops multiple times and use this result in conjunction with a previous construction for a tensor rank drop. Our results also imply strict submultiplicativity for cactus rank and border cactus rank.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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