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arXiv 1802.08796math.AC
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割理想的字典序和逆字典序二次Gröbner基

Lexicographic and reverse lexicographic quadratic Gröbner bases of cut ideals

Ryuichi Sakamoto

摘要:

希比指出,如果一个环面理想有一个二次格罗布纳基,那么这个环面理想有一个字典序或一个逆字典序的二次格罗布纳基。在本文中,我们提出了一个图的割理想,作为这个猜想的一个反例。我们还讨论了圈的割理想的二次Gröbner基的存在性。Nagel和Petrović利用Chifman和Petrović的结果声称一个圈的截理想有一个字典序二次Gröbner基。然而,我们指出,内格尔和彼得罗维奇使用的Chifman和彼得罗维奇的结果是不正确的长度为大于或等于6的循环。因此,一个圈(一个环图)的割理想的二次Gröbner基的存在性是一个开放的问题。我们还提供了一个字典式的二次Gröbner基的切理想的周期长度小于或等于7。

英文摘要:

Hibi conjectured that if a toric ideal has a quadratic Gröbner basis, then the toric ideal has either a lexicographic or a reverse lexicographic quadratic Gröbner basis. In this paper, we present a cut ideal of a graph that serves as a counterexample to this conjecture. We also discuss the existence of a quadratic Gröbner basis of a cut ideal of a cycle. Nagel and Petrović claimed that a cut ideal of a cycle has a lexicographic quadratic Gröbner basis using the results of Chifman and Petrović. However, we point out that the results of Chifman and Petrović used by Nagel and Petrović are incorrect for cycles of length greater than or equal to 6. Hence the existence of a quadratic Gröbner basis for the cut ideal of a cycle (a ring graph) is an open question. We also provide a lexicographic quadratic Gröbner basis of a cut ideal of a cycle of length less than or equal to 7.

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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