منابع مشابه
On T -sequences and characterized subgroups
Let X be a compact metrizable abelian group and u = {un} be a sequence in its dual X. Set su(X) = {x : (un, x) → 1} and T H 0 = {(zn) ∈ T ∞ : zn → 1}. Let G be a subgroup of X. We prove that G = su(X) for some u iff it can be represented as some dually closed subgroup Gu of ClXG × T H 0 . In particular, su(X) is polishable. Let u = {un} be a T -sequence. Denote by (X̂,u) the group X ∧ equipped w...
متن کاملOn T-Characterized Subgroups of Compact Abelian Groups
A sequence {un}n∈ω in abstract additively-written Abelian group G is called a T -sequence if there is a Hausdorff group topology on G relative to which limn un = 0. We say that a subgroupH of an infinite compact Abelian groupX is T -characterized if there is a T -sequence u = {un} in the dual group of X , such that H = {x ∈ X : (un, x) → 1}. We show that a closed subgroupH ofX is T -characteriz...
متن کاملCharacterized Subgroups of Topological Abelian Groups
A subgroup H of a topological abelian group X is said to be characterized by a sequence v = (vn) of characters of X if H = {x ∈ X : vn(x) → 0 in T}. We study the basic properties of characterized subgroups in the general setting, extending results known in the compact case. For a better description, we isolate various types of characterized subgroups. Moreover, we introduce the relevant class o...
متن کاملSOME PROPERTIES OF T-FUZZY GENERALIZED SUBGROUPS
In this paper, we deal with Molaei’s generalized groups. We definethe notion of a fuzzy generalized subgroup with respect to a t-norm (orT-fuzzy generalized subgroup) and give some related properties. Especially,we state and prove the Representation Theorem for these fuzzy generalizedsubgroups. Next, using the concept of continuity of t-norms we obtain a correspondencebetween TF(G), the set of ...
متن کاملAggregating Fuzzy Subgroups and T-vague Groups
Fuzzy subgroups and T -vague groups are interesting fuzzy algebraic structures that have been widely studied. While fuzzy subgroups fuzzify the concept of crisp subgroup, T -vague groups can be identified with quotient groups of a group by a normal fuzzy subgroup and there is a close relation between both structures and T -indistinguishability operators (fuzzy equivalence relations). In this pa...
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ژورنال
عنوان ژورنال: Topology and its Applications
سال: 2010
ISSN: 0166-8641
DOI: 10.1016/j.topol.2010.09.002