TY - JOUR ID - 23682 TI - Density near zero JO - Sahand Communications in Mathematical Analysis JA - SCMA LA - en SN - 2322-5807 AU - Bayatmanesh, Elham AU - Akbari Tootkaboni, Mohammad AD - Department of Mathematics, Faculty of Basic Science, Shahed University, Tehran, Iran. Y1 - 2018 PY - 2018 VL - 09 IS - 1 SP - 33 EP - 43 KW - The Stone-Cech compactification KW - Density KW - Piecewise syndetic set near zero DO - 10.22130/scma.2018.23682 N2 - Let $S$ be a dense subsemigroup of $(0,+\infty)$. In this paper, we state   definition of thick near zero, and also  we will introduce a definition that is equivalent to the definition of piecewise syndetic near zero which presented by Hindman  and Leader in [6].  We define density near zero for subsets of $S$ by a collection of nonempty finite subsets of $S$ and we investigate the conditions under  these concepts. UR - https://scma.maragheh.ac.ir/article_23682.html L1 - https://scma.maragheh.ac.ir/article_23682_545b6075235df500f5ed73aa31024524.pdf ER -