Every tree T determines a set of distinct maximal proper subtrees Ti = T — vi , which are obtained by the deletion of an endpoint of T. In this paper we prove that a tree is almost always uniquely determined by this set of its subtrees, and point out two interesting consequences of this result.In [5], Ulam proposed the following conjecture, which we state in a slightly stronger form due to Harary [1].ULAM'S CONJECTURE. A graph G with at least three points is uniquely determined up to isomorphism by the subgraphs Gi = G — vi .Kelly [4] proved the conjecture for trees and Harary and Palmer [3] showed that not all of the Gi are needed in that case by proving Corollary 1 below. If we remove from the list of subgraphs Gi of a graph G all but one graph of each isomorphism type, we obtain a set of Gi which are distinct up to isomorphism.
@article{10_4153_CJM_1970_007_4,
author = {Manvel, Bennet},
title = {Reconstruction of {Trees}},
journal = {Canadian journal of mathematics},
pages = {55--60},
year = {1970},
volume = {22},
number = {1},
doi = {10.4153/CJM-1970-007-4},
url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1970-007-4/}
}
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AU - Manvel, Bennet
TI - Reconstruction of Trees
JO - Canadian journal of mathematics
PY - 1970
SP - 55
EP - 60
VL - 22
IS - 1
UR - http://geodesic.mathdoc.fr/articles/10.4153/CJM-1970-007-4/
DO - 10.4153/CJM-1970-007-4
ID - 10_4153_CJM_1970_007_4
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%J Canadian journal of mathematics
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%R 10.4153/CJM-1970-007-4
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