نتایج جستجو برای: genus of a graph
تعداد نتایج: 23288361 فیلتر نتایج به سال:
Let R be a commutative ring with non-zero identity. The annihilator-inclusion ideal graph of R , denoted by ξR, is a graph whose vertex set is the of allnon-zero proper ideals of $R$ and two distinct vertices $I$ and $J$ are adjacentif and only if either Ann(I) ⊆ J or Ann(J) ⊆ I. In this paper, we investigate the basicproperties of the graph ξR. In particular, we showthat ξR is a connected grap...
For any $k in mathbb{N}$, the $k$-subdivision of graph $G$ is a simple graph $G^{frac{1}{k}}$, which is constructed by replacing each edge of $G$ with a path of length $k$. In [Moharram N. Iradmusa, On colorings of graph fractional powers, Discrete Math., (310) 2010, No. 10-11, 1551-1556] the $m$th power of the $n$-subdivision of $G$ has been introduced as a fractional power of $G$, denoted by ...
the zero-divisor graph of a commutative ring r with respect to nilpotent elements is a simple undirected graph $gamma_n^*(r)$ with vertex set z_n(r)*, and two vertices x and y are adjacent if and only if xy is nilpotent and xy is nonzero, where z_n(r)={x in r: xy is nilpotent, for some y in r^*}. in this paper, we investigate the basic properties of $gamma_n^*(r)$. we discuss when it will be eu...
Let R be a non-domain commutative ring with identity and A(R) be theset of non-zero ideals with non-zero annihilators. We call an ideal I of R, anannihilating-ideal if there exists a non-zero ideal J of R such that IJ = (0).The annihilating-ideal graph of R is defined as the graph AG(R) with the vertexset A(R) and two distinct vertices I and J are adjacent if and only if IJ =(0). In this paper,...
Let R be a commutative ring with identity and Nil(R) be the set of nilpotent elements of R. The nil-graph of ideals of R is defined as the graph AG_N(R) whose vertex set is {I:(0)and there exists a non-trivial ideal such that and two distinct vertices and are adjacent if and only if . Here, we study conditions under which is complete or bipartite. Also, the independence number of is deter...
چکیده: کنه های خانواده tenuipalpidae گیاهخوار و دارای انتشار جهانی هستند. این گروه از کنه ها به انواع درختان میوه، گیاهان و درختچه های زینتی و درختان جنگلی حمله نموده و علاوه بر تغذیه از شیره گیاهی و تخریب کلروفیل برگ در انتقال بیماریهای ویروسی به گیاهان نقش دارند. لذا شناسایی و مطالعه آنها حائز اهمیت است. در این پژوهش که طی سالهای 90-1389 انجام شد ضمن بررسی فونستیک کنه های تارتن دروغین استان ...
section{introduction} the concept of {sl cartan geometry} appeared at the beginning of the twentieth century, when {e}lie cartan was working on the so-called {sl equivalence problem}, the aim of which is to determine whether two given geometric structures can be mapped bijectively onto each other by some diffeomorphism. this problem can be considered in many different contexts, such as ...
The problem of determining the genus for a graph can be dated to Map Color Conjecture proposed by Heawood in 1890. This was implied Thread Problem Hilbert and Cohn-Vossen. conjecture finally established Ringel, Youngs, many other mathematicians. Subsequently, genera some special graphs with symmetry were determined. study embeddings is closely related invariants graph. Specifically, computation...
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