On sigma-entangled linear orders

关于纠缠线性序的一些问题

Some questions on entangled linear orders

本文在CH假设下研究了纠缠线性序的性质，证明了在不同条件下存在不同纠缠程度的线性序及实数集，探讨了纠缠集与分离性的关系。

Entangledness in Suslin lines and trees

We introduce the idea of a weakly entangled linear order, and show that it is consistent for a Suslin line to be weakly entangled. We generalize the notion of entangled linear orders to $ω_1$-trees, and prove that an $ω_1$-tree is entangled iff it is free. We force the existence of a Suslin tree which is $n$-entangled, but all of whose derived trees of dimension $n+1$ are special, for any positive $n < ω$.