Báo cáo toán học: "nduced trees in triangle-free graphs" pdf

... up-growing induced trees having size at most 2 l = exp(O( √ log n )). Figure 4: Graph G 6 in which all “up-growing trees contain at most two vertices of the uppermost level. 4 Lower bound for triangle-free ... Theorem 1.2 and it serves as an introduction to it. We begin with a lemma about selecting induced forests of a particular kind in a bipartite graph. We introduce some terminolo...

Ngày tải lên: 07/08/2014, 15:23

... bound follows by applying the Stirling approximation formula for factorials. It is worth noting that since every -regular graph with density d and 2n vertices contains, in each color class, at ... bound in Theorem 1 apply this estimate to the matrix A =(a u,v ) u∈V 1 ,v∈V 2 in which a u,v =1if u, v are adjacent and a u,v = 0 otherwise. Here M(G)=per(A). Since the function x! 1/x is inc...

Ngày tải lên: 07/08/2014, 06:22

... question of finding a combinatorial interpretation of the above identity (1.2). In this paper, we obtain a parity reversing involution on noncrossing trees that leads to a combinatorial interpretation ... noncrossing trees with n edges and the set of symmetric ternary trees with n internal vertices. By using even plane trees as an intermediate structure, we may obtain a combinatorial...

Ngày tải lên: 07/08/2014, 13:21

... matching (or one-factor) of G is a subgraph of G in which each vertex has degree at most one. A basic question in combinatorial optimization is, “What is the size of a maximum matching in a given ... The set of incidence vectors of the matchings of G have a convex hull which is equal to the polytope containing all x ∈ R E which satisfy the following the electronic journal of combinatori...

Ngày tải lên: 07/08/2014, 13:21

... t). A join pair (G, t) is a join covered pair if each edge of G lies in a minimum t-join. Note that if T is a t-join in a join pair (G, t) and C is a circuit with more than half its edges in T , ... circuit containing P also contains all the other ears of X, including Q. By the inductive hypothesis, H has a comb T  H , equivalent to T ∩ EH, that has a balanced circuit containing e and...

Ngày tải lên: 07/08/2014, 15:23

... or indeed all higher plants. If we seek meaning in the list as a whole there remains the task of “seeing the wood for the trees , selecting and arranging them into a smaller number of principles ... zonally; A13* Determinate monopodia do not bear indeterminate branches; A14 Indeterminate trunk axes only bear branches con- tinuously if the trunks are orthotropic; A15* Indeterminate branch...

Ngày tải lên: 08/08/2014, 14:22

... giving instructions. T23 felt that a persistence in doing routine activities in Chinese might result in teacher-fronted lessons in which individual students might only be speaking and practicing ... Shih-Chang Hsin. 2011. The development of TCSL teacher training in Taiwan . In Teaching and learning Chinese in global contexts, eds. Linda Tsung and Ken Cruickshank, 165-180. Co...

Ngày tải lên: 20/06/2014, 21:20

... 2007) incorporate boolean rules into constraint-based models for integrated simu- lation of regulatory and metabolic networks. Integrated FBA (iFBA) extends rFBA by integrating kinetic information ... Something from nothing – bridging the gap between constraint-based and kinetic modelling. FEBS J 274(21):5576–5585 Smallbone K, Simeonidis E, Swainston N, Mendes P (2010) Towards a genome-scale...

Ngày tải lên: 20/06/2014, 21:20

Ngày tải lên: 05/08/2014, 09:46

Ngày tải lên: 05/08/2014, 10:20