Centers and shore points of a dendroid

A bottleneck in a dendroid is a continuum that intersects every arc connecting two nonempty open sets. Every dendroid contains a point called a center which is contained in arbitrarily small bottlenecks. A subset A of a dendroid is a shore set if for every ε>0 there is a continuum in D∖A with Hausdorff distance from D less than ε. If a shore set has only one point it is called a shore point. This paper explores the relationship between center points and shore points in a dendroid. We show that if a dendroid contains a strong center, then any finite union of the arc components of the set of shore points is a shore set.