Amenable groups for which very topologically left invariant mean is right invariant

Topologically Left Invariant Mean on Dual Semigroup Algebras

topologically left invariant mean on dual semigroup algebras

Topologically left invariant means on semigroup algebras

Let M(S) be the Banach algebra of all bounded regular Borel measures on a locally compact Hausdorff semitopological semigroup S with variation norm and convolution as multiplication. We obtain necessary and sufficient conditions for M(S)∗ to have a topologically left invariant mean.

Groups with right-invariant multiorders

A Cayley object for a group G is a structure on which G acts regularly as a group of automorphisms. The main theorem asserts that a necessary and sufficient condition for the free abelian group G of rank m to have the generic n-tuple of linear orders as a Cayley object is that m > n. The background to this theorem is discussed. The proof uses Kronecker’s Theorem on diophantine approximation. 1 ...

Amenable Groups with a Locally Invariant Order Are Locally Indicable

We show that every amenable group with a locally invariant partial order has a left-invariant total order (and is therefore locally indicable). We also show that if a group G admits a left-invariant total order, and H is a locally nilpotent subgroup of G, then a left-invariant total order on G can be chosen so that its restriction to H is both left-invariant and right-invariant. Both results fo...