TY - JOUR

T1 - On a theorem of Halin

AU - Imrich, Wilfried

AU - Smith, Simon M.

PY - 2017/10/1

Y1 - 2017/10/1

N2 - This note presents a new, elementary proof of a generalization of a theorem of Halin to graphs with unbounded degrees, which is then applied to show that every connected, countably infinite graph G, with ℵ0≤|Aut(G)|<2ℵ0 and subdegree-finite automorphism group, has a finite set F of vertices that is setwise stabilized only by the identity automorphism. A bound on the size of such sets, which are called distinguishing, is also provided. To put this theorem of Halin and its generalization into perspective, we also discuss several related non-elementary, independent results and their methods of proof.

AB - This note presents a new, elementary proof of a generalization of a theorem of Halin to graphs with unbounded degrees, which is then applied to show that every connected, countably infinite graph G, with ℵ0≤|Aut(G)|<2ℵ0 and subdegree-finite automorphism group, has a finite set F of vertices that is setwise stabilized only by the identity automorphism. A bound on the size of such sets, which are called distinguishing, is also provided. To put this theorem of Halin and its generalization into perspective, we also discuss several related non-elementary, independent results and their methods of proof.

U2 - 10.1007/s12188-016-0167-9

DO - 10.1007/s12188-016-0167-9

M3 - Article

VL - 87.2017

SP - 289

EP - 297

JO - Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg

JF - Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg

SN - 1865-8784

IS - October

ER -