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 共查询到20条相似文献,搜索用时 31 毫秒
1.
We study the stability of non-negative stationary solutions of
where Δp denotes the p-Laplacian operator defined by Δpz = div(zp−2z); p > 2, Ω is a bounded domain in RN(N  1) with smooth boundary where [0,1],h:∂ΩR+ with h = 1 when  = 1, λ > 0, and g:Ω×[0,)→R is a continuous function. If g(xu)/up−1 be strictly increasing (decreasing), we provide a simple proof to establish that every non-trivial non-negative solution is unstable (stable).  相似文献   

2.
Let M1 and M2 be two matroids on the same ground set S. We conjecture that if there do not exist disjoint subsets A1,A2,…,Ak+1 of S, such that ispM1(Ai)≠Ø, and similarly for M2, then S is partitioned into k sets, each independent in both M1 and M2. This is a possible generalization of König's edge-coloring theorem. We prove the conjecture for the case k=2 and for a regular case, in which both matroids have the same rank d, and S consists of k·d elements. Finally, we prove another special case related to a conjecture of Rota.  相似文献   

3.
The main result of our article is an analog of the local manifold theorem for a hyperbolic point. We give a set of sufficient conditions that ensure the existence of the global invariant manifold.

We will prove the existence of invariant curves which lie in the quaternionic Julia set of the map fc(X)=X2+c.  相似文献   


4.
Two uniform asymptotic expansions are obtained for the Pollaczek polynomials Pn(cosθ;a,b). One is for , , in terms of elementary functions and in descending powers of . The other is for , in terms of a special function closely related to the modified parabolic cylinder functions, in descending powers of n. This interval contains a turning point and all possible zeros of Pn(cosθ) in θ(0,π/2].  相似文献   

5.
Izumi Miyamoto   《Discrete Mathematics》2008,308(14):3073-3081
Let G be a doubly but not triply transitive group on a set X. We give an algorithm to construct the orbits of G acting on X×X×X by combining those of its stabilizer H of a point of X If the group H is given first, we compute the orbits of its transitive extension G, if it exists. We apply our algorithm to G=PSL(m,q) and Sp(2m,2), m3, successfully. We go forward to compute the transitive extension of G itself. In our construction we use a superscheme defined by the orbits of H on X×X×X and do not use group elements.  相似文献   

6.
Global stability of a rational difference equation   总被引:1,自引:0,他引:1  
In this paper, we study the global stability of the difference equation , where the parameters a,ai(0,) for i=0,…,k, x-k,…, x-1[0,) and x0(0,). We prove that the unique positive equilibrium is globally asymptotically stable if and only if it is locally asymptotically. Also we provide sufficient condition for it to be globally asymptotically stable and our results solve the open problem proposed by Kulenović and Ladas (Dynamics of Second Order Rational Difference Equations with Open Problems and Conjectures, Chapman & Hall/CRC, Boca Raton, 2002).  相似文献   

7.
E.J. Cheon  T. Kato  S.J. Kim   《Discrete Mathematics》2008,308(14):3082-3089
In this paper, we shall prove that there is no [3q4-q3-q2-3q-1,5,3q4-4q3-2q+1]q code over the finite field for q11. Thus, we conclude the nonexistence of a [gq(5,d),5,d]q code for 3q4-4q3-2q+1d3q4-4q3-q.  相似文献   

8.
We construct a two-point selection , where is the set of the irrational numbers, such that the space is not normal and it is not collectionwise Hausdorff either. Here, τf denotes the topology generated by the two-point selection f. This example answers a question posed by V. Gutev and T. Nogura. We also show that if is a two-point selection such that the topology τf has countable pseudocharacter, then τf is a Tychonoff topology.  相似文献   

9.
Let be a dilation-stable process on . We determine a Hausdorff measure function (a) such that the fractal set X[0,1]={X(t):0t1} has positive finite -measure. We also investigate the packing measure of X[0,1].  相似文献   

10.
This paper deals with p-Laplacian systems
with null Dirichlet boundary conditions in a smooth bounded domain ΩRN, where p,q>1, , and a,b>0 are positive constants. We first get the non-existence result for a related elliptic systems of non-increasing positive solutions. Secondly by using this non-existence result, blow-up estimates for above p-Laplacian systems with the homogeneous Dirichlet boundary value conditions are obtained under Ω=BR={xRN:|x|<R}(R>0). Then under appropriate hypotheses, we establish local theory of the solutions and obtain that the solutions either exists globally or blow-up in finite time.  相似文献   

11.
A group G is said to be a -group if permutability is a transitive relation in the set of all subgroups of G. Our purpose in this paper is to study -groups in the class of periodic radical groups satisfying min-p for all primes p.  相似文献   

12.
We work in set-theory without choice ZF. Denoting by the countable axiom of choice, we show in that the closed unit ball of a uniformly convex Banach space is compact in the convex topology (an alternative to the weak topology in ZF). We prove that this ball is (closely) convex-compact in the convex topology. Given a set I, a real number p1 (respectively p=0), and some closed subset F of [0,1]I which is a bounded subset of p(I), we show that (respectively DC, the axiom of Dependent Choices) implies the compactness of F.  相似文献   

13.
Let be the space of all bounded linear operators on a Banach space X and let LatA be the lattice of invariant subspaces of the operator . We characterize some maps with one of the following preserving properties: Lat(Φ(A)+Φ(B))=Lat(A+B), or Lat(Φ(A)Φ(B))=Lat(AB), or Lat(Φ(A)Φ(B)+Φ(B)Φ(A))=Lat(AB+BA), or Lat(Φ(A)Φ(B)Φ(A))=Lat(ABA), or Lat([Φ(A),Φ(B)])=Lat([A,B]).  相似文献   

14.
In this paper we study and establish central limit theorem behavior in the skew (generalized) tent map transformation T: Y →Y originally considered by Billings and Bollt [Billings L, Bollt EM. Probability density functions of some skew tent maps. Chaos, Solitons & Fractals 2001; 12: 365–376] and Ito et al. [Ito S, Tanaka S, Nakada H. On unimodal linear transformations and chaos. II. Tokyo J Math 1979; 2: 241–59]. When the measure ν is invariant under T, the transfer operator governing the evolution of densities f under the action of the skew tent map, as well as the unique stationary density, are given explicitly for specific transformation parameters. Then, using this development, we solve the Poisson equation for two specific integrable observables and explicitly calculate the variance σ()2=∫Y2(y)ν(dy).  相似文献   

15.
Let A be a complete noetherian regular local ring, and suppose that S is a profinite group acting continuously on A via ring homomorphisms. Let Γ=Mapc(S,A), the algebra of continuous functions from S to A. Then (A,Γ) has a canonical structure of a complete Hopf algebroid, determined by the action of S on A. We give necessary and sufficient conditions for a general complete Hopf algebroid to be of this form. Applications to Morava theory are also discussed.  相似文献   

16.
In the present note, we investigate schemes S in which each element s satisfies ns2 and ns*s≠2. We show that such a scheme is schurian. More precisely, we show that it is isomorphic to G//t, where G is a finite group and t an involution of G weakly closed in CG(t).

Groups G with an involution t weakly closed in CG(t) have been described in Glauberman's Z*-Theorem [G. Glauberman, Central elements in core-free groups, J. Algebra 4 (1966) 403–420] with the help of the largest normal subgroup of G having odd order.  相似文献   


17.
We give deterministic and randomized algorithms to find shortest paths homotopic to a given collection Π of disjoint paths that wind amongst n point obstacles in the plane. Our deterministic algorithm runs in time , and the randomized algorithm runs in expected time O(kout+kinlogn+n(logn)1+ε). Here kin is the number of edges in all the paths of Π, and kout is the number of edges in the output paths.  相似文献   

18.
Let T be a set of n triangles in three-dimensional space, let s be a line segment, and let t be a triangle, both disjoint from T. We consider the subdivision of T based on (in)visibility from s; this is the visibility map of the segment s with respect to T. The visibility map of the triangle t is defined analogously. We look at two different notions of visibility: strong (complete) visibility, and weak (partial) visibility. The trivial Ω(n2) lower bound for the combinatorial complexity of the strong visibility map of both s and t is almost tight: we prove an O(n2(n)) upper bound for both structures, where (n) is the extremely slowly increasing inverse Ackermann function. Furthermore, we prove that the weak visibility map of s has complexity Θ(n5), and the weak visibility map of t has complexity Θ(n7). If T is a polyhedral terrain, the complexity of the weak visibility map is Ω(n4) and O(n5), both for a segment and a triangle. We also present efficient algorithms to compute all discussed structures.  相似文献   

19.
We introduce the concept of N-differential graded algebras (N-dga), and study the moduli space of deformations of the differential of an N-dga. We prove that it is controlled by what we call the (M,N)-Maurer–Cartan equation.  相似文献   

20.
Given a graph G, a proper labeling f of G is a one-to-one function . The bandwidth sum of a graph G, denoted by Bs(G), is defined by Bs(G)=min∑uvE(G)|f(u)-f(v)|, where the minimum is taken for all proper labelings f of G. In this paper, we give some results for the bandwidth sum problem for the join of k graphs G1,G2,…,Gk, where each Gi is a path, cycle, complete graph, or union of isolated vertices. We also discuss the bandwidth sum for the composition of two graphs G and H, where G and H are path, cycle, or union of isolated vertices.  相似文献   

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