Báo cáo toán học: "On a conjecture concerning dyadic oriented matroids" pptx

... subdeterminants are in {±2 k : k ∈ Z}. An oriented matriod is dyadic if it has a totally dyadic represen- tation A. A dyadic oriented matriod is dyadic of order k if it has a totally dyadic representation A ... totally dyadic representation A. A dyadic oriented matriod is dyadic of order k if it has a totally dyadic representation A with full row rank a...

Ngày tải lên: 07/08/2014, 06:20

... interesting classes of non-Cayley graphs and digraphs (generalized Petersen, Kneser, metacirculant and quasi-Cayley) and all four classes contain P 10 . The Petersen graph has long played an important ... that u is adjacent to x i and v is adjacent to x j . Clearly, x i and x j are not adjacent by the girth hypothesis. By Claim 2, graph J 4 contains an induced even path P ij of length a t l...

Ngày tải lên: 08/08/2014, 12:23

... discussions with Eva Czabarka, Ida Kantor, Gyula O.H. Ka t ona, Nathan Lemons, Bal´azs Patk´os, L´aszl´o Sz´ekely, and Jacques Verstra¨ete. The author thanks the NSF for funding her and IPAM for hosting ... (3.17) Since the average degree of a vertex in F ∈ F is greater than k , every set F ∈ F contains a heavy vertex. As F is non-trivial, there are at least two heavy vertices. We conside...

Ngày tải lên: 08/08/2014, 14:22

... t)]   and we already know that the absolute value of the inner sum was found to be smaller than 3 √ q/2. One may extend the codes C(q, n) in a similar way. Using the same approach as that in ... follows that the polynomial P (X)=(X + x)(X + x)(X + y)(X + y) On a Class of Constant Weight Codes Mihai Caragiu Institute of Mathematics Bucharest and Department of Mathematics, Pennsylvania St...

Ngày tải lên: 07/08/2014, 06:20

... The Main Theorem We begin with some preliminaries about partitions and their conjugates. For a given partition π with parts each  N,wedenotebyf i (π) the number of appearances of i as a part ... following be dealing with partitions whose parts are all  some given N.Welet¯π be that partition made up of the parts of π that are <N. In light of (11) we see that if N is a part of π an e...

Ngày tải lên: 07/08/2014, 08:22

... Generalization of Meyniel’s Conjecture on the Cops and Robbers Game Noga Alon ∗ Tel Aviv University and Institute for Advanced Study, Princeton nogaa@tau.ac.il Abbas Mehrabian Department of Combinatorics ... m. Remark. It can be shown using a similar argument that every x ∈ X has at most m neighbors in A. By an escaping pair we mean a pair (x, y) of vertices with x ∈ X and y ∈ N A s...

Ngày tải lên: 08/08/2014, 12:23

... C. Evans, Partial Diff. Equations, American Math. Society, 1998. 5. C. Vargas an d M. Zuluaga, On a Nonlinear Dirichlet Problem Type at Resonance and Bifurcation, Partial Differential Equations, ... Elliptic Equations on an Unbounded Domain Hoang Quoc Toan Fa culty of Math., Mech. and Inform. Vietnam National University, 334 Nguyen Trai, Hanoi, Vietnam Received Ma y 12, 2004 Revised August 28...

Ngày tải lên: 06/08/2014, 05:20

... spaces of random variables, Math. Uspekhi 101 (1976) 417–454 (Russian). 28. V.M. Zolotarev, Ideal metrics in the problems of probability theory and mathe- matical statistics, Austral. J. Statist. ... the approximating type a metric as a comparison measure must be selected in accordance with the requirements to its properties. In recent years several results of applied mathematics and info...

Ngày tải lên: 06/08/2014, 05:20

... these are sophisticated, and the problem serves as a useful study of these techniques, and the algebraic analysis gives partial information about the formulation of a bijective proof. The paper ... t exp wzt 1+zt  , where L (r) w (f)= 1 r! w r ∂ r f ∂w r     w=1 and Θ w : w k → k!w k . The combinatorial nature of the transformations leads one to ask whether combinatorial objects and...

Ngày tải lên: 07/08/2014, 06:20

... Department of Mathematics University of Toronto University of Toronto Toronto, Canada M5S 1A1 Toronto, Canada M5S 1A1 barbeau@math.utoronto.ca tanny@math.utoronto.ca Submitted: January 4, 1996; Accepted: ... metafibonacci type, parameterized by k,and,foreachk, identified what he speculated was the unique increas- ing solution. We show that, to the contrary, there are many increasing solutions...

Ngày tải lên: 07/08/2014, 06:20