Combinatorial theorems about embedding trees on the real line
نویسندگان
چکیده
We consider the combinatorial problem of embedding a tree metric into the real line with low distortion. For two special families of trees — the family of complete binary trees and the family of subdivided stars — we provide embeddings whose distortion is provably optimal, up to a constant factor. We also prove that the optimal distortion of a linear embedding of a tree can be arbitrarily low or high even when it has bounded degree.
منابع مشابه
Embedding theorems for HNN extensions of inverse semigroups
We discuss embedding theorems for HNN extensions and clarify the relationship between the concept by Gilbert and that of Yamamura. We employ the automata theoretical technique based on the combinatorial and geometrical properties of Schützenberger graphs.
متن کاملEgerváry Research Group on Combinatorial Optimization Packing Arborescences Packing Arborescences
In [7], Edmonds proved a fundamental theorem on packing arborescences that has become the base of several subsequent extensions. Recently, Japanese researchers found an unexpected further generalization which gave rise to many interesting questions about this subject [29], [20]. Another line of researches focused on covering intersecting families which generalizes Edmonds' theorems in a di eren...
متن کاملSingularities of Piecewise Linear Mappings. I Mappings into the Real Line
In this note we consider piecewise linear mappings of combinatorial manifolds into the real line. We define—in a purely combinatorial way—a certain class of mappings called nondegenerate and we prove that every continuous mapping may be approximated by a nondegenerate one. Nondegenerate mappings on a combinatorial manifold behave like differentiable nondegenerate mappings on a differentiate man...
متن کاملSperner and Kkm-type Theorems on Trees and Cycles
In this paper we prove a new combinatorial theorem for labellings of trees, and show that it is equivalent to a KKM-type theorem for finite covers of trees and to discrete and continuous fixed point theorems on finite trees. This is in analogy with the equivalence of the classical Sperner’s lemma, KKM lemma, and the Brouwer fixed point theorem on simplices. Furthermore, we use these ideas to de...
متن کاملPhishing website detection using weighted feature line embedding
The aim of phishing is tracing the users' s private information without their permission by designing a new website which mimics the trusted website. The specialists of information technology do not agree on a unique definition for the discriminative features that characterizes the phishing websites. Therefore, the number of reliable training samples in phishing detection problems is limited. M...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of Graph Theory
دوره 67 شماره
صفحات -
تاریخ انتشار 2011