Positroid包络与图论positroid
Positroid envelopes and graphic positroids
AI总结：
本文通过显式图构造证明每个positroid包络类含图拟阵，并证明图论positroid在包络类中唯一，且可由非负子式符号关联矩阵表示。
摘要：
Positroids是由所有非负极大子式的实矩阵可实现的拟阵。它们通过Grassmann项链将有序拟阵划分为等价类，称为positroid包络类。我们给出了一个显式的图构造，表明每个positroid包络类都包含一个图拟阵。我们证明了一个图论positroid是其positroid包络类中的唯一拟阵。最后，我们证明了每个图论positroid都有一个有向图，可由带所有非负子式的符号关联矩阵表示。
英文摘要：
Positroids are matroids realizable by real matrices with all nonnegative maximal minors. They partition the ordered matroids into equivalence classes, called positroid envelope classes, by their Grassmann necklaces. We give an explicit graph construction that shows that every positroid envelope class contains a graphic matroid. We prove that a graphic positroid is the unique matroid in its positroid envelope class. Finally, we show that every graphic positroid has an oriented graph representable by a signed incidence matrix with all nonnegative minors.
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。
