论文标题
来自关联方案图的量子同构
Quantum isomorphism of graphs from association schemes
论文作者
论文摘要
我们表明,相同数量的顶点上的任何两个Hadamard图都是量子同构。这是从更一般的配方来表现出由某些关联方案引起的图形量子同构的。主要结果是由三个工具构建的。 Mančinska和Roberson的一个了不起的结果表明,当且仅当对于任何平面图$ f $的情况下,图形$ g $和$ h $是量子同构的,则图形同构的数量从$ f $到$ g $等于从$ f $ to $ h $ h $ f $ f $ f $ f $ f $ f $ f $ f $ f $。称为“支架”的分区函数的概括提供了一些基本的还原规则,例如串联并行减少,可以应用于计数同构。最终的工具是Epifanov的经典定理,表明任何平面图都可以通过扩展的串联串联降低和Delta-Wye变换来简化为单个顶点,而没有边缘。如果确切的三重常规关联方案,我们可以使用这种最后的转换。该论文包括开放问题和未来研究的方向。
We show that any two Hadamard graphs on the same number of vertices are quantum isomorphic. This follows from a more general recipe for showing quantum isomorphism of graphs arising from certain association schemes. The main result is built from three tools. A remarkable recent result of Mančinska and Roberson shows that graphs $G$ and $H$ are quantum isomorphic if and only if, for any planar graph $F$, the number of graph homomorphisms from $F$ to $G$ is equal to the number of graph homomorphisms from $F$ to $H$. A generalization of partition functions called "scaffolds" affords some basic reduction rules such as series-parallel reduction and can be applied to counting homomorphisms. The final tool is the classical theorem of Epifanov showing that any plane graph can be reduced to a single vertex and no edges by extended series-parallel reductions and Delta-Wye transformations. This last sort of transformation is available to us in the case of exactly triply regular association schemes. The paper includes open problems and directions for future research.