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Lexico extension and a cut completion of a half l-group

Štefan Černák, Milan Demko (2002)

Discussiones Mathematicae - General Algebra and Applications

The cut completi on of an hl-group G with the abelian increasing part is investigated under the assumption that G is a lexico extension of its hl-subgroup.

Local/global uniform approximation of real-valued continuous functions

Anthony W. Hager (2011)

Commentationes Mathematicae Universitatis Carolinae

For a Tychonoff space X , C ( X ) is the lattice-ordered group ( l -group) of real-valued continuous functions on X , and C * ( X ) is the sub- l -group of bounded functions. A property that X might have is (AP) whenever G is a divisible sub- l -group of C * ( X ) , containing the constant function 1, and separating points from closed sets in X , then any function in C ( X ) can be approximated uniformly over X by functions which are locally in G . The vector lattice version of the Stone-Weierstrass Theorem is more-or-less equivalent...

Locally solid topological lattice-ordered groups

Liang Hong (2015)

Archivum Mathematicum

Locally solid Riesz spaces have been widely investigated in the past several decades; but locally solid topological lattice-ordered groups seem to be largely unexplored. The paper is an attempt to initiate a relatively systematic study of locally solid topological lattice-ordered groups. We give both Roberts-Namioka-type characterization and Fremlin-type characterization of locally solid topological lattice-ordered groups. In particular, we show that a group topology on a lattice-ordered group is...

Monotone σ-complete groups with unbounded refinement

Friedrich Wehrung (1996)

Fundamenta Mathematicae

The real line ℝ may be characterized as the unique non-atomic directed partially ordered abelian group which is monotone σ-complete (countable increasing bounded sequences have suprema), has the countable refinement property (countable sums m a m = n b n of positive (possibly infinite) elements have common refinements) and is linearly ordered. We prove here that the latter condition is not redundant, thus solving an old problem by A. Tarski, by proving that there are many spaces (in particular, of arbitrarily...

Nearly disjoint sequences in convergence l -groups

Ján Jakubík (2000)

Mathematica Bohemica

For an abelian lattice ordered group G let G be the system of all compatible convergences on G ; this system is a meet semilattice but in general it fails to be a lattice. Let α n d be the convergence on G which is generated by the set of all nearly disjoint sequences in G , and let α be any element of G . In the present paper we prove that the join α n d α does exist in G .

Normalization of M V -algebras

Ivan Chajda, Radomír Halaš, Jan Kühr, Alena Vanžurová (2005)

Mathematica Bohemica

We consider algebras determined by all normal identities of M V -algebras, i.e. algebras of many-valued logics. For such algebras, we present a representation based on a normalization of a sectionally involutioned lattice, i.e. a q -lattice, and another one based on a normalization of a lattice-ordered group.

On absolute retracts and absolute convex retracts in some classes of l-groups

Ján Jakubík (2003)

Discussiones Mathematicae - General Algebra and Applications

By dealing with absolute retracts of l-groups we use a definition analogous to that applied by Halmos for the case of Boolean algebras. The main results of the present paper concern absolute convex retracts in the class of all archimedean l-groups and in the class of all complete l-groups.

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