Expansion Properties Of Levi Graphs
نویسندگان
چکیده
The Levi graph of a balanced incomplete block design is the bipartite graph whose vertices are the points and blocks of the design, with each block adjacent to those points it contains. We derive upper and lower bounds on the isoperimetric numbers of such graphs, with particular attention to the special cases of finite projective planes and Hadamard designs.
منابع مشابه
I-graphs and the Corresponding Configurations
We consider the class of I-graphs I(n, j, k), which is a generalization over the class of the generalized Petersen graphs. We study different properties of I-graphs such as connectedness, girth and whether they are bipartite or vertex-transitive. We give an efficient test for isomorphism of I-graphs and characterize the automorphism groups of I-graphs. Regular bipartite graphs with girth at lea...
متن کاملHypergraph expanders from Cayley graphs
We present a simple mechanism, which can be randomised, for constructing sparse 3-uniform hypergraphs with strong expansion properties. These hypergraphs are constructed using Cayley graphs over Z2 and have vertex degree which is polylogarithmic in the number of vertices. Their expansion properties, which are derived from the underlying Cayley graphs, include analogues of vertex and edge expans...
متن کاملEdge Expansion of Cubical Complexes
In this paper we show that graphs of “neighbourly” cubical complexes – cubical complexes in which every pair of vertices spans a (unique) cube – have good expansion properties, using a technique based on multicommodity flows. By showing that graphs of stable set polytopes are graphs of neighbourly cubical complexes we give a new proof that graphs of stable set polytopes have edge expansion 1.
متن کاملSome Algebraic and Combinatorial Properties of the Complete $T$-Partite Graphs
In this paper, we characterize the shellable complete $t$-partite graphs. We also show for these types of graphs the concepts vertex decomposable, shellable and sequentially Cohen-Macaulay are equivalent. Furthermore, we give a combinatorial condition for the Cohen-Macaulay complete $t$-partite graphs.
متن کاملExpansion Properties of Large Social Graphs
Social network analysis has become an extremely popular research area, where the main focus is the understanding of networks’ structure. In this paper, we study the expansibility of large social graphs, a structural property based on the notion of expander graphs (i.e. sparse graphs with strong connectivity properties). It is widely believed that social networks have poor expansion properties, ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Ars Comb.
دوره 80 شماره
صفحات -
تاریخ انتشار 2006