Polynomial products modulo primes and applications

Monatshefte für Mathematik - For any polynomial $$P(x)in {mathbb {Z}}[x],$$ we study arithmetic dynamical systems generated by $$displaystyle {F_P(n)=mathop {prod nolimits _{kle...     

Boolean techniques for matroidal decomposition of independence systems and applications to graphs

The problem of decomposing an independence system into the set-theoretic union of matroids is considered in the first part of this paper and a Boolean procedure is proposed for finding the prime matroidal components of such a decomposition. The second part of the paper deals with the special case of the independence system of all stable sets of a graph, characterizes the graphs whose family of stable sets is the set-theoretic union of two matroids, produces a class of perfect graphs of matroidal number k and gives for graphs an accelerated version of the general decomposition technique.     

Reversible $$G^k$$ G k -codes with applications to DNA codes

Designs, Codes and Cryptography - In this paper, we give a matrix construction method for designing DNA codes that come from group matrix rings. We show that with our construction one can obtain...     

A cascade decomposition theory with applications to Markov and exchangeable cascades

A multiplicative random cascade refers to a positive -martingale in the sense of Kahane on the ultrametric space A new approach to the study of multiplicative cascades is introduced. The methods apply broadly to the problems of: (i) non-degeneracy criterion, (ii) dimension spectra of carrying sets, and (iii) divergence of moments criterion. Specific applications are given to cascades generated by Markov and exchangeable processes, as well as to homogeneous independent cascades.

     

Graph decomposition with constraints on the connectivity and minimum degree

For each pair s,t of natural numbers there exist natural numbers f(s,t) and g(s,t) such that the vertex set of each graph of connectivity at least f(s,t) (respectively minimum degree at least g(s,t)) has a decomposition into sets which induce subgraphs of connectivity (respectively minimum degree) at least s and t, respectively.     

Symmetric-triangular decomposition and its applications part II: Preconditioners for indefinite systems

As an application of the symmetric-triangular (ST) decomposition given by Golub and Yuan (2001) and Strang (2003), three block ST preconditioners are discussed here for saddle point problems. All three preconditioners transform saddle point problems into a symmetric and positive definite system. The condition number of the three symmetric and positive definite systems are estimated. Therefore, numerical methods for symmetric and positive definite systems can be applied to solve saddle point problems indirectly. A numerical example for the symmetric indefinite system from the finite element approximation to the Stokes equation is given. Finally, some comments are given as well. AMS subject classification (2000) 65F10     

A toric Positivstellensatz with applications to delay systems

The structure of positive polynomials on a torus is derived from recent results of real algebraic geometry. As an application, we propose some simple conditions for testing the hyperbolicity/stability of a generic class of linear systems of retarded type.     

均衡二部图中含2k条指定边的k个独立圈及2-因子

得到了对于二部图G=(V_1,V_2;E),当|V_1|=|V_2|=n≥2k+1时的结果:对G中任意2k条独立边e_1,e_1~*,…,e_k,e_k~*,G中一定存在k个独立的4-圈C_1,C_2,…,C_k,使得对任意i∈{1,2,…,k}有{e_i,e_i~*}E(C_i).并在此基础上进一步证明了当|V_1|=|V_2|=n≥3k时若对任意两顶点x∈V_1,y∈V_2,都有d(x)+d(y)≥2n-k+1成立,则G有一个2-因子含有k+1个独立圈C_1,C_2,…,C_(k+1)使得对任意i∈{1,2,…,k}有{e_i,e_i~*}E(C_i)且|C_i|=4.     

Convergence in gradient-like systems with applications to PDE

In gradient-like systems, the limit set of an orbit belongs to the set of equilibrium points. We give easily applied conditions to determine when this limit set is a single point. Applications are given to parabolic equations, linearly damped hyperbolic equations as well as their discretizations.Dedicated to Klaus Kirchgässner on his 60th birthday     

On the controllability of nonlinear systems with applications to polynomial systems

The purpose of this paper is to examine the controllability for a class of nonlinear control systems of the form $$\frac{{d\phi t}}{{dt}} = X_0 (\phi t) + \sum\limits_{j = 1}^r {u_j (t)X_j } (\phi _t )$$ Our general theorem is stated in terms of differential geometry, but it will be applied to concrete systems such that coefficientsX ₀,..,X _r are polynomials.     

Powers of rationals modulo 1 and rational base number systems

A new method for representing positive integers and real numbers in a rational base is considered. It amounts to computing the digits from right to left, least significant first. Every integer has a unique expansion. The set of expansions of the integers is not a regular language but nevertheless addition can be performed by a letter-to-letter finite right transducer. Every real number has at least one such expansion and a countable infinite number of them have more than one. We explain how these expansions can be approximated and characterize the expansions of reals that have two expansions. The results that we derive are pertinent on their own and also as they relate to other problems in combinatorics and number theory. A first example is a new interpretation and expansion of the constant K(p) from the so-called “Josephus problem.” More important, these expansions in the base allow us to make some progress in the problem of the distribution of the fractional part of the powers of rational numbers. Work partially supported by the CNRS/JSPS contract 13 569, and by the “ACI Nouvelles Interfaces des Mathématiques”, contract 04 312.     

A generalization of Dijkstra's shortest path algorithm with applications to VLSI routing

We generalize Dijkstra's algorithm for finding shortest paths in digraphs with non-negative integral edge lengths. Instead of labeling individual vertices we label subgraphs which partition the given graph. We can achieve much better running times if the number of involved subgraphs is small compared to the order of the original graph and the shortest path problems restricted to these subgraphs is computationally easy.As an application we consider the VLSI routing problem, where we need to find millions of shortest paths in partial grid graphs with billions of vertices. Here, our algorithm can be applied twice, once in a coarse abstraction (where the labeled subgraphs are rectangles), and once in a detailed model (where the labeled subgraphs are intervals). Using the result of the first algorithm to speed up the second one via goal-oriented techniques leads to considerably reduced running time. We illustrate this with a state-of-the-art routing tool on leading-edge industrial chips.     

Subsolutions and super solutions to systems of parabolic equations with applications to generalized Fujita-type systems

A constructive method for obtaining subsolutions and supersolutions to the Cauchy problem for systems of parabolic equations is discussed. Applications of the method to Fujita-type systems are considered leading to global existence and finite time blow-up results.     

Automorphisms on a Lie group contracting modulo a compact subgroup and applications to semistable convolution semigroups

Let ( _t ) _t0 be a -semistable convolution semigroup of probability measures on a Lie groupG whose idempotent ₀ is the Haar measure on some compact subgroupK. Then all the measures ₁ are supported by theK-contraction groupC _K() of the topological automorphism ofG. We prove here the structure theoremC _K()=C()K, whereC() is the contraction group of . Then it turns out that it is sufficient to study semistable convolution semigroups on simply connected nilpotent Lie groups that have Lie algebras with a positive graduation.     

A canonical decomposition for quadratic forms with applications to monotone convergence theorems

We prove monotone convergence theorems for quadratic forms on a Hilbert space which improve existing results. The main tool is a canonical decomposition for any positive quadratic form h = h_r + h_s where h_r is characterized as the largest closable form smaller than h. There is also a systematic discussion of nondensely defined forms.     

Some properties on G-evaluation and its applications to G-martingale decomposition

In this article, a sublinear expectation induced by G-expectation is introduced, which is called G- evaluation for convenience. As an application, we prove that for any ξ ∈ L β G (Ω T ) with some β > 1 the martingale decomposition theorem under G-expectaion holds, and that any β > 1 integrable symmetric G-martingale can be represented as an Ito integral w.r.t. G-Brownian motion. As a byproduct, we prove a regularity property for G-martingales: Any G-martingale {M t } has a quasi-continuous version.