Journal of the London Mathematical Society Advance Access originally published online on January 12, 2007
Journal of the London Mathematical Society 2007 75(1):35-46; doi:10.1112/jlms/jdl004
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© 2007 London Mathematical Society
One-sided ideals and right cancellation in the second dual of the group algebra and similar algebras
Department of Mathematical Sciences
University of Oulu
PL 3000
90014 Oulun Yliopisto
Finland
mahmoud.filali{at}oulu.fi
pekka.salmi{at}oulu.fi
The following results are proved for a non-compact, locally compact group G: the dimension of every non-trivial right ideal in L1(G)** (equipped with the first Arens product) is at least
, where
(G) is the minimal number of compact sets required to cover G; there exist
left ideals in L1(G)** and in LUC(G)* with trivial intersections, and the linear span of right-cancellable elements is weak*-dense in the annihilator of C0(G) in LUC(G)* and in the annihilator of
(the L
-functions that vanish at infinity) in L
(G)*. The same results are proved for weighted algebras when the weight function is diagonally bounded.
2000 Mathematics Subject Classification 43A20 (primary), 22D15, 22A15 (secondary).
Received June 16, 2004; revised July 11, 2005; published online January 12, 2007.