ﻻ يوجد ملخص باللغة العربية
The lakes of Wada are three disjoint simply connected domains in $S^2$ with the counterintuitive property that they all have the same boundary. The common boundary is a indecomposable continuum. In this article we calculated the Minkowski dimension of such boundaries. The lakes constructed in the standard Cantor way has $ln(6)/ln(3)approx 1.6309$-dimensional boundary, while in general, for any number in $[1,2]$ we can construct lakes with such dimensional boundaries.
For a metric space $X$, let $mathsf FX$ be the space of all nonempty finite subsets of $X$ endowed with the largest metric $d^1_{mathsf FX}$ such that for every $ninmathbb N$ the map $X^ntomathsf FX$, $(x_1,dots,x_n)mapsto {x_1,dots,x_n}$, is non-exp
Let us define for a compact set $A subset mathbb{R}^n$ the sequence $$ A(k) = left{frac{a_1+cdots +a_k}{k}: a_1, ldots, a_kin Aright}=frac{1}{k}Big(underset{k {rm times}}{underbrace{A + cdots + A}}Big). $$ It was independently proved by Shapley, Folk
In the following, bypassing dynamical systems tools, we propose a simple means of computing the box dimension of the graph of the classical Weierstrass function defined, for any real number~$x$, by~$ {cal W}(x)=displaystyle sum_{n=0}^{+infty} lambda^
As proved by Dimov [Acta Math. Hungarica, 129 (2010), 314--349], there exists a duality L between the category HLC of locally compact Hausdorff spaces and continuous maps, and the category DHLC of complete local contact algebras and appropriate morph
P.J. Nyikos has asked whether it is consistent that every hereditarily normal manifold of dimension > 1 is metrizable, and proved it is if one assumes the consistency of a supercompact cardinal, and, in addition, that the manifold is hereditarily col