منابع مشابه
Tree-visibility Orders Tree-visibility Orders
In this paper we introduce a new class of partially ordered sets, called tree-visibility orders, extending the class of interval orders in a fashion similar to the extension of interval graphs to chordal graphs. This class contains interval orders, duals of generalized interval orders and height one orders. We give a characterization of tree-visibility orders by an innnite family of minimal for...
متن کاملTree-visibility orders
We introduce a new class of partially ordered sets, called tree-visibility orders, containing interval orders, duals of generalized interval orders and height one orders. We give a characterization of tree-visibility orders by an innnite family of minimal forbidden suborders. Furthermore we present an eecient recognition algorithm for tree-visibility orders.
متن کاملTree-automatic scattered linear orders
We study tree-automatic linear orders on regular tree languages. We first show that there is no tree-automatic scattered linear order, and in particular no well-order, on the set of all finite labeled trees. This also follows from results of Gurevich-Shelah [8] and Carayol-Löding [4]. We then show that a regular tree language admits a tree-automatic scattered linear order if and only if all tre...
متن کاملRegular tree languages and quasi orders
Regular languages were characterized as sets closed with respect to monotone well-quasi orders. A similar result is proved here for tree languages. Moreover, families of quasi orders that correspond to positive varieties of tree languages and varieties of finite ordered algebras are characterized.
متن کاملSearching in Dynamic Tree-Like Partial Orders
We give the first data structure for the problem of maintaining a dynamic set of n elements drawn from a partially ordered universe described by a tree. We define the Line-Leaf Tree, a linear-sized data structure that supports the operations: insert; delete; test membership; and predecessor. The performance of our data structure is within an O(logw)-factor of optimal. Here w ≤ n is the width of...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1998
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(98)00041-7