A sofic approximation to a countable group is a sequence of partial actions on finite sets that asymptotically approximates the action of the group on itself by left-translations. A group is sofic if it admits a sofic approximation. Sofic entropy theory is a generalization of classical entropy theory in dynamics to actions by sofic groups. However, the sofic entropy of an action may depend on a choice of sofic approximation. All previously known examples showing this dependence rely on degenerate behavior. This paper exhibits an explicit example of a mixing subshift of finite type with two different positive sofic entropies. The example is inspired by statistical physics literature on 2-colorings of random hyper-graphs.
翻译:与可计算组群的近似值是定数组的一组部分动作,这些动作通过左译法不时地近似于该组群本身的动作。 如果一个组群接受一种悬浮近似值, 则该组体会非常之高。 Sofic entropy 理论是典型的昆虫理论的概括化, 与safic 组群的动作相适应。 然而, 一项动作的振动性能可能取决于对定数的近似值的选择。 所有以前已知的显示这种依赖性的例子都依赖于堕落的行为。 本文展示了一个明显的例子, 即有限类型子变形与两种不同的正显性超大动因混合。 这个例子的灵感来自关于随机高压图的2色统计物理文献。