Luc Guyot |
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Limits of finite groups |
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Determining which
groups can arise as limits of finite groups is an exciting but seemingly
difficult question.
We shall treat the most elementary cases : limits of cyclic groups and dihedral groups in the space of finitely generated groups. For both classes, the solution is surprisingly easy. Indeed, we are able to make a list of the very restricted isomorphism types occuring as limits. We also characterize these limits in terms of universal theory (sentences in the language of group theory with a single "∃" symbol at the beginning) in the spirit of a theorem of Remeslennikov on limits of free groups. |