|
Journal of Lie Theory 30 (2020), No. 4, 965--980 Copyright Heldermann Verlag 2020 Topologically Simple, Totally Disconnected, Locally Compact Infinite Matrix Groups Peter Groenhout The University of Newcastle, Callaghan 2308, NSW, Australia peter.groenhout@uon.edu.au George A. Willis The University of Newcastle, Callaghan 2308, NSW, Australia george.willis@newcastle.edu.au Colin D. Reid The University of Newcastle, Callaghan 2308, NSW, Australia colin@reidit.net We construct uncountably many non-locally isomorphic examples of topologically simple nondiscrete totally disconnected locally compact groups. The new examples differ from known examples of such groups in that they have trivial quasi-centre, but also have infinite abelian locally normal subgroups. The examples are constructed as almost upper-triangular matrices modulo scalar matrices over finite fields, where "almost upper-triangular" is defined with respect to one of an uncountable family of preorders generalising the natural orders on the set of integers and the set of natural numbers. Keywords: Infinite matrix, finite field, locally compact group, topologically simple, quasi-centre. MSC: 22D05; 20H30, 20E18. [ Fulltext-pdf (149 KB)] for subscribers only. |