Consider a connected r-regular n-vertex graph G with random independent edge lengths, each uniformly distributed on (0, 1). Let mst(G) be the expected length of a minimum spanning tree. We show that mst(G) can be estimated quite accurately under two distinct circumstances. Firstly, if r is large and G has a modest edge expansion property then mst(G) ∼ n r ζ (3), where ζ(3) = ∞ j=1 j −3 ∼ 1.202. Secondly, if G has large girth then there exists an explicitly defined constant cr such that mst(G) ∼ crn. We find in particular that c 3 = 9/2 − 6 log 2 ∼ 0.341.
In a Maker-Breaker game on a graph G, Breaker and Maker alternately claim edges of G. Maker wins if, after all edges have been claimed, the graph induced by his edges has some desired property. We consider four Maker-Breaker games played on random geometric graphs. For each of our four games we show that if we add edges between n points chosen uniformly at random in the unit square by order of increasing edge-length then, with probability tending to one as n → ∞, the graph becomes Maker-win the very moment it satisfies a simple necessary condition. In particular, with high probability, Maker wins the connectivity game as soon as the minimum degree is at least two; Maker wins the Hamilton cycle game as soon as the minimum degree is at least four; Maker wins the perfect matching game as soon as the minimum degree is at least two and every edge has at least three neighbouring vertices; and Maker wins the H-game as soon as there is a subgraph from a finite list of "minimal graphs". These results also allow us to give precise expressions for the limiting probability that G(n, r) is Maker-win in each case, where G(n, r) is the graph on n points chosen uniformly at random on the unit square with an edge between two points if and only if their distance is at most r.
This paper describes the design, manufacture, testing and analysis of two model heterogeneous materials that exhibit non classical elastic behaviour when loaded. In particular both materials demonstrate a size effect in which stiffness increases as test sample size reduces; an effect that is unrecognized by classical elasticity but predicted by more generalized elasticity theories that are thought to describe the behaviour of heterogeneous materials more fully. The size effect has been observed by both experimental testing and finite element analysis that fully incorporates the details of the underlying heterogeneity designed into each material. The size effect has been quantified thus enabling both the modulus and also the characteristic length, an additional constitutive parameter present within micropolar and other generalized elasticity theories, to be determined for each material. These characteristic length values are extraordinarily similar to the length scales associated with the structure of the materials. An additional constitutive parameter present within plane micropolar elasticity theory that quantifies shear stress asymmetry has also been determined for one of the materials by using an iterative process that seeks to minimize the differences between numerical predictions and test results
In this paper the mechanical behaviour of model heterogeneous materials consisting of regular periodic arrays of circular voids within a polymeric matrix is investigated. Circular ring samples of the materials were fabricated by machining the voids into commercially available polymer sheet. Ring samples of differing sizes but similar geometries were loaded using mechanical testing equipment. Sample stiffness was found to depend on sample size with stiffness increasing as size reduced. The periodic nature of the void arrays also facilitated detailed finite element analysis of each sample. The results obtained by analysis substantiate the observed dependence of stiffness on size. Classical elasticity theory does not acknowledge this size effect but more generalized elasticity theories do predict it. Micropolar elasticity theory has therefore been used to interpret the sample stiffness data and identify constitutive properties. Modulus values for the model materials have been quantified. Values of two additional constitutive properties, the characteristic length and the coupling number, which are present within micropolar elasticity but absent from its classic counterpart have also been determined. The dependence of these additional properties on void size has been investigated and characteristic length values compared to the length scales inherent within the structure of the model materials.
Abstract. We consider a game that can be viewed as a random graph process. The game has two players and begins with the empty graph on vertex set [n]. During each turn a pair of random edges is generated and one of the players chooses one of these edges to be an edge in the graph. Thus the players guide the evolution of the graph as the game is played. One player controls the even rounds with the goal of creating a so-called giant component as quickly as possible. The other player controls the odd rounds and has the goal of keeping the giant from forming for as long as possible. We show that the product rule is an asymptotically optimal strategy for both players.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.