We consider the outer automorphism group Out(AΓ) of the right-angled Artin group AΓ of a random graph Γ on n vertices in the Erdős–Rényi model. We show that the functions n−1(log(n) + log(log(n))) and 1 − n−1(log(n) + log(log(n))) bound the range of edge probability functions for which Out(AΓ) is finite: if the probability of an edge in Γ is strictly between these functions as n grows, then asymptotically Out(AΓ) is almost surely finite, and if the edge probability is strictly outside of both of these functions, then asymptotically Out(AΓ) is almost surely infinite. This sharpens a result of Ruth Charney and Michael Farber.
Keywords: right-angled Artin group, random graph, automorphism group of group
Day, Matthew B  1
@article{10_2140_agt_2012_12_1553,
author = {Day, Matthew B},
title = {Finiteness of outer automorphism groups of random right-angled {Artin} groups},
journal = {Algebraic and Geometric Topology},
pages = {1553--1583},
year = {2012},
volume = {12},
number = {3},
doi = {10.2140/agt.2012.12.1553},
url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2012.12.1553/}
}
TY - JOUR AU - Day, Matthew B TI - Finiteness of outer automorphism groups of random right-angled Artin groups JO - Algebraic and Geometric Topology PY - 2012 SP - 1553 EP - 1583 VL - 12 IS - 3 UR - http://geodesic.mathdoc.fr/articles/10.2140/agt.2012.12.1553/ DO - 10.2140/agt.2012.12.1553 ID - 10_2140_agt_2012_12_1553 ER -
%0 Journal Article %A Day, Matthew B %T Finiteness of outer automorphism groups of random right-angled Artin groups %J Algebraic and Geometric Topology %D 2012 %P 1553-1583 %V 12 %N 3 %U http://geodesic.mathdoc.fr/articles/10.2140/agt.2012.12.1553/ %R 10.2140/agt.2012.12.1553 %F 10_2140_agt_2012_12_1553
Day, Matthew B. Finiteness of outer automorphism groups of random right-angled Artin groups. Algebraic and Geometric Topology, Tome 12 (2012) no. 3, pp. 1553-1583. doi: 10.2140/agt.2012.12.1553
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