0 Rigidity properties of diagram groups
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چکیده
In this paper we establish a rigid connection between two classical objects: the R.Thompson group (the group of all piece-wise linear homeomorphisms of the unit interval with finitely many dyadic break points and all slopes powers of 2) and the Dunce hat (the topological space obtained from the triangle ABC by gluing AB, BC and AC). We prove that a diagram group of a directed 2-complex contains a copy of the R.Thompson group if and only if the 2-complex contains a copy of the Dunce hut.
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تاریخ انتشار 2000