کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4659011 1344299 2013 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
More on convergent sequences in free topological groups
ترجمه فارسی عنوان
بیشتر در دنباله های همگرا در گروه های توپولوژی آزاد
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات هندسه و توپولوژی
چکیده انگلیسی

We show that, for every infinite cardinal τ, there exists a zero-dimensional pseudocompact space X   with |X|=τω|X|=τω such that all countable subsets of X are closed (hence all compact subsets of X   are finite), but both the free Abelian topological group A(X)A(X) and the free topological group F(X)F(X) on X contain a compact subspace of cardinality τ. This answers a recent question raised by A.V. Arhangelʼskii. We also show that there exists a countably compact space Y   without infinite compact subsets such that the groups F(Y)F(Y) and A(Y)A(Y) contain the one-point compactification of a discrete space of cardinality 2c2c (under additional set-theoretic assumptions, the groups F(Y)F(Y) and A(Y)A(Y) can contain arbitrarily big compact subsets).If, however, X   is homeomorphic to a topological group, then the existence of an infinite compact subset of F(X)F(X) (or A(X)A(X)) implies that X contains an infinite compact subset as well.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Topology and its Applications - Volume 160, Issue 11, 1 July 2013, Pages 1206–1213
نویسندگان
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