# Classification and discrete cocompact subgroups of some 7-dimensional connected nilpotent groups

Author: Milnes, P.

Source: Acta Mathematica Hungarica, Volume 109, Number 3, October 2005 , pp. 191-213(23)

Publisher: Springer

OR

Price: $47.00 plus tax (Refund Policy) Abstract: For real connected nilpotent groups, 7 is the lowest dimension where there are infinitely many non-isomorphic groups, and also where some groups (indeed, uncountably many) have no discrete cocompact subgroups. In [21] one infinite family ]]>]]>]]>]]>]]>]]>]]>\mathcal{G}$ of 7-dimensional groups was identified and classified. Discrete cocompact subgroups H were identified for some groups in $\mathcal{G}$ in [10], along with simple quotients of $C^{*}(\mathrm{H})$ and relevant flows $(\mathrm{H}_3,\mathbf{T}^3)$. In this paper, such H and attributes are determined for more groups in $\mathcal{G}$; in particular, the members of $\mathcal{G}$ that admit discrete cocompact subgroups are identified precisely. In achieving some of these results, we consider other known ways of classifying the groups in $\mathcal{G}$, and also the classification of the analogous family of complex groups.

Document Type: Research Article

Publication date: October 1, 2005

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