On fibers and accessibility of groups acting on trees with inversions

• Veröffentlicht in: Algebra and Discrete Mathematics
• Datum: 2015
• 1. Verfasser: Mahmood, R.M.S.
• Format: Artikel
• Sprache: Englisch
• Veröffentlicht: Інститут прикладної математики і механіки НАН України 2015
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/154252
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: On fibers and accessibility of groups acting on trees with inversions / R.M.S. Mahmood // Algebra and Discrete Mathematics. — 2015. — Vol. 19, № 2. — С. 229-242. — Бібліогр.: 11 назв. — англ.

Throughout this paper the actions of groups on
 graphs with inversions are allowed. An element g of a group G is
 called inverter if there exists a tree X where G acts such that g
 transfers an edge of X into its inverse. A group G is called accessible
 if G is finitely generated and there exists a tree on which G acts
 such that each edge group is finite, no vertex is stabilized by G, and
 each vertex group has at most one end.
 In this paper we show that if G is a group acting on a tree
 X such that if for each vertex v of X, the vertex group Gv of v
 acts on a tree Xv, the edge group Ge of each edge e of X is finite
 and contains no inverter elements of the vertex group Gt(e) of the
 terminal t(e) of e, then we obtain a new tree denoted Xe and is called
 a fiber tree such that G acts on Xe. As an application, we show that
 if G is a group acting on a tree X such that the edge group Ge for
 each edge e of X is finite and contains no inverter elements of Gt(e),
 the vertex Gv group of each vertex v of X is accessible, and the
 quotient graph G /X for the action of G on X is finite, then G is
 an accessible group.