منابع مشابه
Relaxed Graceful Labellings of Trees
A graph G on m edges is considered graceful if there is a labelling f of the vertices of G with distinct integers in the set {0, 1, . . . ,m} such that the induced edge labelling g defined by g(uv) = |f(u) − f(v)| is a bijection to {1, . . . ,m}. We here consider some relaxations of these conditions as applied to tree labellings: 1. Edge-relaxed graceful labellings, in which repeated edge label...
متن کاملModular Edge-Graceful Trees
Ryan Jones, Western Michigan University We introduce a modular edge-graceful labeling of a graph a dual concept to the common graceful labeling. A 1991 conjecture known as the Modular Edge-Graceful Tree Conjecture states that every tree of order n where n 6≡ 2 (mod 4) is modular edge-graceful. We show that this conjecture is true. More general results and questions on this topic are presented.
متن کاملImproved Models for Graceful Graphs
The problem of finding a graceful labelling of a graph, or proving that the graph is not graceful, has previously been modelled as a CSP. A new and much faster CSP model of the problem has been recently proposed. This model was inspired by a mathematical proof. We present a third model that is in some sense a combination of the previous two, but is much more efficient than either. We give sever...
متن کاملGraceful Tree Conjecture for Infinite Trees
One of the most famous open problems in graph theory is the Graceful Tree Conjecture, which states that every finite tree has a graceful labeling. In this paper, we define graceful labelings for countably infinite graphs, and state and verify a Graceful Tree Conjecture for countably infinite trees.
متن کاملA Survey of Graceful Trees
A tree of order n is said to be graceful if the vertices can be assigned the labels {0, . . . , n−1} such that the absolute value of the differences in vertex labels between adjacent vertices generate the set {1, . . . , n− 1}. The Graceful Tree Conjecture is the unproven claim that all trees are graceful. We present major results known on graceful trees from those dating from the problem’s ori...
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ژورنال
عنوان ژورنال: Graphs and Combinatorics
سال: 2017
ISSN: 0911-0119,1435-5914
DOI: 10.1007/s00373-017-1757-8