Asymmetric tie-points and almost clopen subsets of $\mathbb {N}^*$
نویسندگان
چکیده
منابع مشابه
Commutativity degree of $mathbb{Z}_p$≀$mathbb{Z}_{p^n}
For a nite group G the commutativity degree denote by d(G) and dend:$$d(G) =frac{|{(x; y)|x, yin G,xy = yx}|}{|G|^2}.$$ In [2] authors found commutativity degree for some groups,in this paper we nd commutativity degree for a class of groups that have high nilpontencies.
متن کاملHardness of almost embedding simplicial complexes in $\mathbb R^d$
A map f : K → R of a simplicial complex is an almost embedding if f(σ) ∩ f(τ) = ∅ whenever σ, τ are disjoint simplices of K. Theorem. Fix integers d, k ≥ 2 such that d = 3k 2 + 1. (a) Assume that P 6= NP . Then there exists a finite k-dimensional complex K that does not admit an almost embedding in R but for which there exists an equivariant map K̃ → Sd−1. (b) The algorithmic problem of recognit...
متن کاملClopen Graphs
A graph G on a topological space X as its set of vertices is clopen if the edge relation of G is a clopen subset of X2 without the diagonal. We study clopen graphs on Polish spaces in terms of their finite induced subgraphs and obtain information about their cochromatic numbers. In this context we investigate modular profinite graphs, a class of graphs obtained from finite graphs by taking inve...
متن کاملFrames for subspaces of $\mathbb{C}^N$
We present a theory of finite frames for subspaces of C N. The definition of a subspace frame is given and results analogous to those from frame theory for C N are proven.
متن کاملAlmost Disjoint Large Subsets of Semigroups
There are several notions of largeness in a semigroup S that originated in topological dynamics. Among these are thick , central , syndetic and piecewise syndetic. Of these, central sets are especially interesting because they are partition regular and are guaranteed to contain substantial combinatorial structure. It is known that in (N,+) any central set may be partitioned into infinitely many...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Commentationes Mathematicae Universitatis Carolinae
سال: 2019
ISSN: 0010-2628,1213-7243
DOI: 10.14712/1213-7243.2015.268