Distinguishability of locally finite trees
The electronic journal of combinatorics, Tome 14 (2007)
The distinguishing number $\Delta(X)$ of a graph $X$ is the least positive integer $n$ for which there exists a function $f:V(X)\to\{0,1,2,\cdots,n-1\}$ such that no nonidentity element of $\hbox{Aut}(X)$ fixes (setwise) every inverse image $f^{-1}(k)$, $k\in\{0,1,2,\cdots,n-1\}$. All infinite, locally finite trees without pendant vertices are shown to be 2-distinguishable. A proof is indicated that extends 2-distinguishability to locally countable trees without pendant vertices. It is shown that every infinite, locally finite tree $T$ with finite distinguishing number contains a finite subtree $J$ such that $\Delta(J)=\Delta(T)$. Analogous results are obtained for the distinguishing chromatic number, namely the least positive integer $n$ such that the function $f$ is also a proper vertex-coloring.
DOI :
10.37236/947
Classification :
05C05, 05C12
Mots-clés : distinguishing number, chromatic number
Mots-clés : distinguishing number, chromatic number
@article{10_37236_947,
author = {Mark E. Watkins and Xiangqian Zhou},
title = {Distinguishability of locally finite trees},
journal = {The electronic journal of combinatorics},
year = {2007},
volume = {14},
doi = {10.37236/947},
zbl = {1112.05026},
url = {http://geodesic.mathdoc.fr/articles/10.37236/947/}
}
Mark E. Watkins; Xiangqian Zhou. Distinguishability of locally finite trees. The electronic journal of combinatorics, Tome 14 (2007). doi: 10.37236/947
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