ترغب بنشر مسار تعليمي؟ اضغط هنا

Binomial Edge Ideals of Generalized block graphs

134   0   0.0 ( 0 )
 نشر من قبل Arvind Kumar Mr.
 تاريخ النشر 2019
  مجال البحث
والبحث باللغة English
 تأليف Arvind Kumar




اسأل ChatGPT حول البحث

We classify generalized block graphs whose binomial edge ideals admit a unique extremal Betti number. We prove that the Castelnuovo-Mumford regularity of binomial edge ideals of generalized block graphs is bounded below by $m(G)+1$, where $m(G)$ is the number of minimal cut sets of the graph $G$ and obtain an improved upper bound for the regularity in terms of the number of maximal cliques and pendant vertices of $G$.



قيم البحث

اقرأ أيضاً

168 - Johannes Rauh 2012
This paper studies a class of binomial ideals associated to graphs with finite vertex sets. They generalize the binomial edge ideals, and they arise in the study of conditional independence ideals. A Grobner basis can be computed by studying paths in the graph. Since these Grobner bases are square-free, generalized binomial edge ideals are radical. To find the primary decomposition a combinatorial problem involving the connected components of subgraphs has to be solved. The irreducible components of the solution variety are all rational.
105 - Rajib Sarkar 2019
Let $G$ be a connected simple graph on the vertex set $[n]$. Banerjee-Betancourt proved that $depth(S/J_G)leq n+1$. In this article, we prove that if $G$ is a unicyclic graph, then the depth of $S/J_G$ is bounded below by $n$. Also, we characterize $ G$ with $depth(S/J_G)=n$ and $depth(S/J_G)=n+1$. We then compute one of the distinguished extremal Betti numbers of $S/J_G$. If $G$ is obtained by attaching whiskers at some vertices of the cycle of length $k$, then we show that $k-1leq reg(S/J_G)leq k+1$. Furthermore, we characterize $G$ with $reg(S/J_G)=k-1$, $reg(S/J_G)=k$ and $reg(S/J_G)=k+1$. In each of these cases, we classify the uniqueness of extremal Betti number of these graphs.
In this paper we prove the conjectured upper bound for Castelnuovo-Mumford regularity of binomial edge ideals posed in [23], in the case of chordal graphs. Indeed, we show that the regularity of any chordal graph G is bounded above by the number of m aximal cliques of G, denoted by c(G). Moreover, we classify all chordal graphs G for which L(G) = c(G), where L(G) is the sum of the lengths of longest induced paths of connected components of G. We call such graphs strongly interval graphs. Moreover, we show that the regularity of a strongly interval graph G coincides with L(G) as well as c(G).
94 - Arvind Kumar 2019
Let $G$ be a simple graph on $n$ vertices. Let $L_G text{ and } mathcal{I}_G : $ denote the Lovasz-Saks-Schrijver(LSS) ideal and parity binomial edge ideal of $G$ in the polynomial ring $S = mathbb{K}[x_1,ldots, x_n, y_1, ldots, y_n] $ respectively. We classify graphs whose LSS ideals and parity binomial edge ideals are complete intersections. We also classify graphs whose LSS ideals and parity binomial edge ideals are almost complete intersections, and we prove that their Rees algebra is Cohen-Macaulay. We compute the second graded Betti number and obtain a minimal presentation of LSS ideals of trees and odd unicyclic graphs. We also obtain an explicit description of the defining ideal of the symmetric algebra of LSS ideals of trees and odd unicyclic graphs.
We determine the Castelnuovo-Mumford regularity of binomial edge ideals of complement reducible graphs (cographs). For cographs with $n$ vertices the maximum regularity grows as $2n/3$. We also bound the regularity by graph theoretic invariants and c onstruct a family of counterexamples to a conjecture of Hibi and Matsuda.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا