Displaying 121 – 140 of 152

Showing per page

Distributivity of bounded lattices with sectionally antitone involutions

Ivan Chajda (2005)

Discussiones Mathematicae - General Algebra and Applications

We present a simple condition under which a bounded lattice L with sectionally antitone involutions becomes an MV-algebra. In thiscase, L is distributive. However, we get a criterion characterizingdistributivity of L in terms of antitone involutions only.

Distributivity of strong implications over conjunctive and disjunctive uninorms

Daniel Ruiz-Aguilera, Joan Torrens (2006)

Kybernetika

This paper deals with implications defined from disjunctive uninorms U by the expression I ( x , y ) = U ( N ( x ) , y ) where N is a strong negation. The main goal is to solve the functional equation derived from the distributivity condition of these implications over conjunctive and disjunctive uninorms. Special cases are considered when the conjunctive and disjunctive uninorm are a t -norm or a t -conorm respectively. The obtained results show a lot of new solutions generalyzing those obtained in previous works when the implications...

Divisibility in certain automorphism groups

Ramiro H. Lafuente-Rodríguez (2007)

Czechoslovak Mathematical Journal

We study solvability of equations of the form x n = g in the groups of order automorphisms of archimedean-complete totally ordered groups of rank 2. We determine exactly which automorphisms of the unique abelian such group have square roots, and we describe all automorphisms of the general ones.

DMF-algebras: representation and topological characterization

Maurizio Negri (1998)

Bollettino dell'Unione Matematica Italiana

Gli insiemi parziali sono coppie A , B di sottoinsiemi di X , dove A B 0 . Gli insiemi parziali su X costituiscono una DMF-algebra, ossia un'algebra di De Morgan in cui la negazione ha un solo punto fisso. Dimostriamo che ogni DMF-algebra è isomorfa a un campo di insiemi parziali. Utilizzando gli insiemi parziali su X come aperti, introduciamo il concetto di spazio topologico parziale su X . Infine associamo ad ogni DMF-algebra A uno spazio topologico parziale i cui clopen compatti costituiscono un campo d'insiemi...

Domain representability of C p ( X )

Harold Bennett, David Lutzer (2008)

Fundamenta Mathematicae

Let C p ( X ) be the space of continuous real-valued functions on X, with the topology of pointwise convergence. We consider the following three properties of a space X: (a) C p ( X ) is Scott-domain representable; (b) C p ( X ) is domain representable; (c) X is discrete. We show that those three properties are mutually equivalent in any normal T₁-space, and that properties (a) and (c) are equivalent in any completely regular pseudo-normal space. For normal spaces, this generalizes the recent result of Tkachuk that C p ( X ) is...

Domain-representable spaces

Harold Bennett, David Lutzer (2006)

Fundamenta Mathematicae

We study domain-representable spaces, i.e., spaces that can be represented as the space of maximal elements of some continuous directed-complete partial order (= domain) with the Scott topology. We show that the Michael and Sorgenfrey lines are of this type, as is any subspace of any space of ordinals. We show that any completely regular space is a closed subset of some domain-representable space, and that if X is domain-representable, then so is any G δ -subspace of X. It follows that any Čech-complete...

Dominating analytic families

Anastasis Kamburelis (1998)

Fundamenta Mathematicae

Let A be an analytic family of sequences of sets of integers. We show that either A is dominated or it contains a continuum of almost disjoint sequences. From this we obtain a theorem by Shelah that a Suslin c.c.c. forcing adds a Cohen real if it adds an unbounded real.

Domination properties in ordered Banach algebras

H. du T. Mouton, S. Mouton (2002)

Studia Mathematica

We recall from [9] the definition and properties of an algebra cone C of a real or complex Banach algebra A. It can be shown that C induces on A an ordering which is compatible with the algebraic structure of A. The Banach algebra A is then called an ordered Banach algebra. An important property that the algebra cone C may have is that of normality. If C is normal, then the order structure and the topology of A are reconciled in a certain way. Ordered Banach algebras have interesting spectral properties....

Doubly stochastic matrices and the Bruhat order

Richard A. Brualdi, Geir Dahl, Eliseu Fritscher (2016)

Czechoslovak Mathematical Journal

The Bruhat order is defined in terms of an interchange operation on the set of permutation matrices of order n which corresponds to the transposition of a pair of elements in a permutation. We introduce an extension of this partial order, which we call the stochastic Bruhat order, for the larger class Ω n of doubly stochastic matrices (convex hull of n × n permutation matrices). An alternative description of this partial order is given. We define a class of special faces of Ω n induced by permutation matrices,...

Currently displaying 121 – 140 of 152