arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1508.03166math.GRmath.CO
收藏

自由群上的计数函数与自由幺半群的关系

Relations between counting functions on free groups and free monoids

Tobias Hartnick, Alexey Talambutsa

摘要:

我们考虑自由群$F_n$和$n \geq 2$的自由幺半群$M_n$上计数函数的有限和。如果两个这样的和相差有界函数,则认为它们是等价的。我们找到了计数函数的和的等价类之间的线性关系的完整集合,并应用这个结果来构造这样的等价类的向量空间的一个明确的基础。此外,我们提供了一个图形算法来确定是否两个给定的计数函数的总和是等价的。特别是,这产生了一个算法,以决定是否两个布鲁克斯拟同构的总和$F_n$代表同一类的有界上同调。

英文摘要:

We consider finite sums of counting functions on the free group $F_n$ and the free monoid $M_n$ for $n \geq 2$. Two such sums are considered equivalent if they differ by a bounded function. We find the complete set of linear relations between equivalence classes of sums of counting functions and apply this result to construct an explicit basis for the vector space of such equivalence classes. Moreover, we provide a graphical algorithm to determine whether two given sums of counting functions are equivalent. In particular, this yields an algorithm to decide whether two sums of Brooks quasimorphisms on $F_n$ represent the same class in bounded cohomology.

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。

↑