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arXiv 2103.10370math.CO
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生成树上的Torsor结构

Torsor Structures on Spanning Trees

Farbod Shokrieh, Cameron Wright

摘要:

研究了(度0)Picard群在有限带状图的生成树集合上的两个作用.已知这两个动作分别表示为$β_q$和$ρ_q$,当且仅当带状图是平面的时,它们独立于基顶点$q$。Baker和Wang证明了在无重边的非平面带状图中,总存在一个点$q$,使$ρ_q\neqβ_q$ .证明了这个猜想,并将其推广到一类具有重边的带状图。我们也给出明确的例子,探索在非平面的情况下,两个torsor结构之间的关系。

英文摘要:

We study two actions of the (degree 0) Picard group on the set of the spanning trees of a finite ribbon graph. It is known that these two actions, denoted $β_q$ and $ρ_q$ respectively, are independent of the base vertex $q$ if and only if the ribbon graph is planar. Baker and Wang conjectured that in a nonplanar ribbon graph without multiple edges there always exists a vertex $q$ for which $ρ_q\neqβ_q$. We prove the conjecture and extend it to a class of ribbon graphs with multiple edges. We also give explicit examples exploring the relationship between the two torsor structures in the nonplanar case.

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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