1,720,992 research outputs found
S(n)-theta-closed spaces
No full textA new class of spaces is introduced in analogy to the S(n)-spaces. Variation of the theta-closure operators are used to describe various features of these categories
Closure operators I
No full textAn abstract notion of closure operator is proposed with numerous applications in topology, algebra and sicrete matehmatics
Epis in categories of convergence spaces
No full textWith respect to a closure operator C in a topological category X, subcategories of X are defined by using C in terms of separation axioms such as T_0 and T_1. Then the
epis are found these categories. By taking a particular closure operator K, results about epis and co-wellpoweredness are obtained in case X=Fil, Lim, PsT, PrT, some of which are not true when X is the category of all topological spaces
Closure operators induced by topological epireflections
No full textClosure operators in the category of topological spaces are studied in connection to epimorphisms
Compactness, minimality and closedness with respect to a closure operator
No full textFor an arbitrarily fixed closure operator in a topological category compactness, closedness and minimality are studied and compared
On E-dense hulls and shape theory,
No full textCharacterizations of epidense subcategories of topological categories and of existence of epidense hulls have been described in [2, 3, 4]. In this paper a similar characterization is given in a much more general setting; for example the category need not have products. The relationship between finite factorization structures and existence of epidense hulls is investigated. It is found to be analogous to the relationship between general factorization structures and epireflective hulls
Topological categories and closure operators
No full textA non-additive closure operator in topological catedories is studie
ON EPIDENSE SUBCATEGORIES OF TOPOLOGICAL CATEGORIES
No full textDense subcategories were introduced by S. Mardešić for an inverse system approach to (categorical) shape theory.
In this paper some internal characterizations of (epi,bi)dense subcategories of a topological category are given. We also show that if K A is a bidense subcategory then the “best approximation” of an A-object X by a K-inverse system is obtained by “modifications” of the structure of X
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