Search

In this paper we prove a Markov theorem for virtual braids and for analogs of this structure including flat virtual braids and welded braids. The virtual braid group is the natural companion to the category of virtual knots, just as the Artin braid group is the natural companion to classical knots and links. In this paper we follow L-move methods to prove the Virtual Markov theorems. One benefit of this approach is a fully local algebraic formulation of the theorems in each category. [ABSTRACT FROM AUTHOR]

In this paper we construct a gathering process by the means of which we obtain new normal forms in braid groups. The new normal forms generalize Artin–Markoff normal forms and possess an extremely natural geometric description. In the two last sections of the paper we discuss the implementation of the introduced gathering process and the questions that arose in our work. This discussion leads us to some interesting observations, in particular, we offer a method of generating a random braid. [ABSTRACT FROM AUTHOR]

Groups with triality, which arose in the papers of Glauberman and Doro, are naturally connected with Moufang loops. In this paper, we describe all possible, in a sense, groups with triality associated with a given Moufang loop. We also introduce several universal groups with triality and discuss their properties. [ABSTRACT FROM AUTHOR]

In this paper, attribute reduction in variable precision rough set model is discussed. Several kinds of reducts preserving some of lower approximations, upper approximations, boundary regions and the unpredictable region are discussed. Relations among those kinds of reducts are investigated. As a basis for reduct computation, Boolean function representations of the preservation of lower approximations, upper approximations, boundary regions and the unpredictable region are discussed. Throughout this paper, the great difference between the analysis using variable precision rough sets and the classical rough set analysis is emphasized. [ABSTRACT FROM AUTHOR]

In this paper, we reexamine the foundation of Isaacs' π-theory. One of the key concepts in Isaacs' π-theory is the construction of the characters Bπ(G) for a π-separable group G. The key to determining which characters lie in Bπ(G) was the construction of a nucleus for each irreducible character χ. In this paper, we present a different way of finding a nucleus for χ which is based on a chain of normal subgroup $\mathcal{N}$. Using this nucleus, we obtain the set of characters $B_{\pi}(G:\mathcal{N})$. We investigate the properties that $B_{\pi}(G:\mathcal{N})$ has in common with Bπ(G). [ABSTRACT FROM AUTHOR]

This paper deals with the mathematical analysis of a model of urban dynamics, which was proposed by Miyata and Yamaguchi in the context of a region of Japan. The model is a complex system of first-order nonlinear ordinary differential equations. The study undertaken by Miyata and Yamaguchi is essentially computational, while an extensive study of the asymptotic behavior of the solutions is performed in this paper related to a detailed analysis of the qualitative properties of the system. [ABSTRACT FROM AUTHOR]

The debate about the non-locality of quantum mechanics is old, but still lively. Numerous people use non-locality as (bad) shorthand for quantum entanglement. But some have a long-standing commitment to the validity of this characterization. This paper examines two separate streams in this debate. The first is the arguments of Stapp, and especially his recent paper where he simplifies his contractual argument in the Hardy situation to argue for the non-locality of quantum mechanics. He has maintained his contention that an analysis of a Hardy-type correlation between two spatially separated observers proves that quantum mechanics itself is non-local, without any additional assumption of realism or hidden variables. In the second section, I try to carefully examine the Bell argument in the CHSH variant to see where the difference between the quantum and classical situations differ. Asher Peres was one of the great physicists of the late 20th century, especially for his intense concern with the fundamental nature of quantum mechanics. His courage in devoting his life to an area many considered "philosophical" (i.e. non-physical) paved the way for the rest of us to reveal our interests and confusions about this area. I am not sure that he would agree with everything in this paper, but I offer it as a tribute to him. [ABSTRACT FROM AUTHOR]

(Co)induction functors appear in several areas of Algebra in different forms. Interesting examples are the so called induction functors in the Theory of Affine Algebraic Groups. In this paper we investigate Hopf pairings (bialgebra pairings) and use them to study (co)induction functors for affine group schemes over arbitrary commutative ground rings. We present also a special type of Hopf pairings (bialgebra pairings) satisfying the so called α-condition. For those pairings the coinduction functor is studied and nice descriptions of it are obtained. Along the paper several interesting results are generalized from the case of base fields to the case of arbitrary commutative (Noetherian) ground rings. [ABSTRACT FROM AUTHOR]

In this paper we study prime preradicals, irreducible preradicals, ∧-prime preradicals, prime submodules and diuniform modules. We study some relations between these concepts, using the lattice structure of preradicals developed in previous papers. In particular, we give a characterization of prime preradicals using an operator named the relative annihilator. We also characterize prime submodules by means of prime preradicals. We give some characterizations of rings that have certain conditions on prime radicals and on irreducible preradicals, such as left local left V-rings, as well as 1-spr rings, which we introduce. [ABSTRACT FROM AUTHOR]

This paper is concerned with the Einstein vacuum equations under the additional assumption of T3-Gowdy symmetry. We prove that there is a generic set of initial data such that the corresponding solutions exhibit curvature blow up on a dense subset of the singularity. By generic, we mean a countable intersection of open sets (i.e. a Gδ set) which is also dense. Furthermore, the set of initial data is given the C∞ topology. This result was presented at a conference in Miami 2004. Recently, we have obtained a stronger result, but the argument to prove it is different and much longer. Therefore, we here wish to present the original argument. Finally, combining the results presented here with a paper by Chruściel and Lake, one obtains strong cosmic censorship for T3-Gowdy spacetimes. [ABSTRACT FROM AUTHOR]

In this paper, we discuss a simple, Monte Carlo algorithm for the problem of checking whether a Quantified Boolean Formula (QBF) in Conjunctive Normal Form (CNF), with at most two literals per clause has a model. The term k-CNF is used to describe boolean formulas in CNF, with at most /c literals per clause and the problem of checking whether a given k-CNF formula is satisfiable is called the k-SAT problem. A QBF is a boolean formula, accompanied by a quantifier string which imposes a linear ordering on the variables of that formula. The problem of finding a model for a QBF formula in CNF, with at at most k literals per clause is called the QkSAT problem. The QkSAT problem is PSPACE-complete, for k ≥ 3. However, the Q2SAT problem can be decided in polynomial time; the graph-based procedure, discussed in [1], is the first such algorithm for this problem. This procedure requires the construction of a global implication graph, corresponding to the input formula and searching for certain paths in this graph. Hence the complete set of clauses must be part of the input. We propose an incremental, randomized approach for the Q2SAT problem that is essentially local in nature, in that the complete clausal set need not be provided at any time, in the presence of a verifier. We show that the randomized algorithm can be analyzed as a one-dimensional random walk, with one reflecting barrier and one absorbing barrier. On a Q2SAT instance with in clauses on n variables, our coin-flipping algorithm runs in time O(n² V(m, n)), where V(m, n) is the time required to verify that a given model satisfies the formula. Additionally, if the instance is satisfiable, the probability that our algorithm fails to find a model is less than one half. The design and analysis of a randomized algorithm for a problem, is important from both the theoretical and the practical perspectives. Randomized approaches tend to be simple and elegant, thereby making the process of checking correctness, effortless as well. The randomized approach discussed in this paper lays the groundwork for analyzing a number of problems related to 2CNF formulas and directed graphs. We remark that our work in this paper is the first randomized algorithm for a class of QBFs. [ABSTRACT FROM AUTHOR]

Let m,n ∈ ℕ. We define $B_{n,m}(\mathbb{S}^{2})$ to be the set of (n+m)-braids of the sphere whose associated permutation lies in the subgroup Sn × Sm of the symmetric group Sn+m on n+m letters. In a previous paper [13], we showed that if n ≥ 3, then there exists the following generalisation of the Fadell–Neuwirth short exact sequence: \[ 1\to B_m(\mathbb{S}^{2}\setminus\{x_1,\ldots,x_n\})\to B_{n,m}(\mathbb{S}^{2})\stackrel{p_{\ast}}{\longrightarrow} B_n(\mathbb{S}^{2})\to 1, \] where ${p_{\ast}}{:}\, B_{n,m}(\mathbb{S}^{2}) \to B_n(\mathbb{S}^{2})$ is the group homomorphism (defined for all n ∈ ℕ) given geometrically by forgetting the last m strings. In this paper we study the splitting of this short exact sequence, as well as the existence of a cross-section for the fibration $p{:}\, D_{n,m}(\mathbb{S}^{2}) \to D_n(\mathbb{S}^{2})$ of the quotients of the corresponding configuration spaces. Our main results are as follows: if n = 1 (respectively, n = 2) then the homomorphism p* and the fibration p admit (respectively, do not admit) a section. If n = 3, then p* and p admit a section if and only if m ≡ 0,2 (mod 3). If n ≥ 4, we show that if p* and p admit a section then m ≡ ε1(n - 1)(n - 2) - ε2n(n - 2) (mod n(n - 1)(n - 2)), where ε1,ε2 ∈ {0,1}. Finally, we show that $B_n(\mathbb{S}^{2})$ is generated by two of its torsion elements. [ABSTRACT FROM AUTHOR]

This paper studies the two-dimensional range search problem, and constructs a simple and efficient algorithm based on the Voronoi diagram. In this problem, a set of points and a query range are given, and we want to enumerate all the points which are inside the query range as quickly as possible. In most of the previous researches on this problem, the shape of the query range is restricted to particular ones such as circles, rectangles and triangles, and the improvement on the worst-case performance has been pursued. On the other hand, the algorithm proposed in this paper is designed for a general shape of the query range in the two-dimensional space, and is intended to accomplish a good average-case performance. This performance is actually observed by numerical experiments. In these experiments, we compare the execution time of the proposed algorithm with those of other representative algorithms such as those based on the bucketing technique and the k-d tree. We can observe that our algorithm shows the better performance in almost all the cases. [ABSTRACT FROM AUTHOR]

We show how to prescribe the initial data of a characteristic problem satisfying the constraints, the smallness, the regularity and the asymptotic decay suitable to prove a global existence result. In this paper, the first of two, we show in detail the construction of the initial data and give a sketch of the existence result. This proof, which mimicks the analogous one for the non-characteristic problem in [19], will be the content of a subsequent paper. [ABSTRACT FROM AUTHOR]

Many of the tools of dynamical systems and control theory have gone largely unused for fluids, because the governing equations are so dynamically complex, both high-dimensional and nonlinear. Model reduction involves finding low-dimensional models that approximate the full high-dimensional dynamics. This paper compares three different methods of model reduction: proper orthogonal decomposition (POD), balanced truncation, and a method called balanced POD. Balanced truncation produces better reduced-order models than POD, but is not computationally tractable for very large systems. Balanced POD is a tractable method for computing approximate balanced truncations, that has computational cost similar to that of POD. The method presented here is a variation of existing methods using empirical Gramians, and the main contributions of the present paper are a version of the method of snapshots that allows one to compute balancing transformations directly, without separate reduction of the Gramians; and an output projection method, which allows tractable computation even when the number of outputs is large. The output projection method requires minimal additional computation, and has a priori error bounds that can guide the choice of rank of the projection. Connections between POD and balanced truncation are also illuminated: in particular, balanced truncation may be viewed as POD of a particular dataset, using the observability Gramian as an inner product. The three methods are illustrated on a numerical example, the linearized flow in a plane channel. [ABSTRACT FROM AUTHOR]

Illuminative deformation patterns of a honeycomb structure are presented. A representative volume element of a honeycomb structure consisting of 2 × 2 hexagonal cells is modeled to be a ${\rm D}_6\dot{+}({\rm C}_2\times\tilde{\rm C}_2)$-equivariant system. The bifurcation mechanism and an exhaustive list of possible bifurcated patterns are obtained by group-theoretic bifurcation theory. A flower mode of the honeycomb is shown to have the same symmetry as the so-called anti-hexagon in the Rayleigh–Bénard convection. A numerical bifurcation analysis is conducted on an elastic in-plane honeycomb structure consisting of 2×2 cells to produce beautiful wallpapers of bifurcating deformation patterns and, in turn, to highlight the achievement of the paper. New deformation patterns of a honeycomb structure have been found and classified in a systematic manner. Knowledge of the symmetries of the bifurcating solutions has turned out to be vital in the successful numerical tracing of the bifurcated paths. This paper paves the way for the introduction of the results hitherto obtained for flow patterns in fluid dynamics into the study of patterns on materials. [ABSTRACT FROM AUTHOR]

In this paper we present a simulation of an acyclic n×n DR-Mesh on an n×n LR-Mesh. The simulation is efficient in regards to size since both models use the same number of processors. The worst execution time for this simulation is O(n2) time, but we demonstrate that its average execution time is O(logn). The fastest existing simulation takes O(logn) time, but it uses an extremely large number of processors. On the other hand, the most efficient simulation in terms of size takes O(log2n) time with O(n4/log2n) processors. Both of the existing simulations are for the unrestricted DR-Mesh. This paper provides an important step towards efficiently simulating the unrestricted DR-Mesh on weaker models such as the R-Mesh and the LR-Mesh. [ABSTRACT FROM AUTHOR]

This paper proposes a procedure to design fault tolerant algorithms for the R-Mesh and some of its restrictive variations. This procedure first identifies a healthy sub-mesh from a faulty model using the bypass and removal fault model. Then it uses scalable algorithms to simulate the larger faulty model on the resulting healthy sub-mesh. The algorithms for the bypass model tolerates n faults in an n×n R-Mesh (LR-Mesh) and runs in O(T log n) (O(T)) time, where T is the execution time on the original mesh without faults. For the removal model, we design fault tolerant algorithms for some interesting variations of the R-Mesh, specifically, the NXR-Mesh and the NXLR-Mesh. We propose the first scaling simulations for these models and present a simulation of the R-Mesh on the NXR-Mesh. The results of this paper enable us to consider certain reconfigurable models in a more practical environment than previously allowed. [ABSTRACT FROM AUTHOR]

The subject of this paper is a generalized approach to relative scalar cardinalities of fuzzy sets. In the main part of the paper, we discuss basic properties of triangular norm-based relative cardinality such as valuation property, the cartesian product rule and complementary rule. Examples of cardinalities satisfying those properties are also given. [ABSTRACT FROM AUTHOR]

In a recent paper, Altenbernd, Thomas and Wöhrle have considered acceptance of languages of infinite two-dimensional words (infinite pictures) by finite tiling systems, with the usual acceptance conditions, such as the Büchi and Muller ones, firstly used for infinite words. The authors asked for comparing the tiling system acceptance with an acceptance of pictures row by row using an automaton model over ordinal words of length ω2. We give in this paper a solution to this problem, showing that all languages of infinite pictures which are accepted row by row by Büchi or Choueka automata reading words of length ω2 are Büchi recognized by a finite tiling system, but the converse is not true. We give also the answer to two other questions which were raised by Altenbernd, Thomas and Wöhrle, showing that it is undecidable whether a Büchi recognizable language of infinite pictures is E-recognizable (respectively, A-recognizable). [ABSTRACT FROM AUTHOR]

A system that consists of a damped oscillator impacting two immovable fenders has been considered in this paper. In the first part a method of analytical determination of the existence of periodic solutions to the equations of motion and a method of analysis of the stability of these solutions have been presented. The results of the computations carried out by means of these methods have been illustrated by a few examples. In the second part of the paper, the results of some numerical investigations have been presented. The goal of these studies was to determine, in which regions of parameters characterizing the system, the motion of the oscillator is periodic and stable. [ABSTRACT FROM AUTHOR]

By applying the undetermined coefficient method, this paper finds homoclinic and heteroclinic orbits in the Chen system. It analytically demonstrates that the Chen system has one heteroclinic orbit of Ši'lnikov type that connects two nontrivial singular points. The Ši'lnikov criterion guarantees that the Chen system has Smale horseshoes and the horseshoe chaos. In addition, there also exists one homoclinic orbit joined to the origin. The uniform convergence of the series expansions of these two types of orbits are proved in this paper. It is shown that the heteroclinic and homoclinic orbits together determine the geometric structure of Chen's attractor. [ABSTRACT FROM AUTHOR]

For any C¹ differential system S on a compact Riemannian manifold M of dimension d with d ≥= 2, this paper studies the Liao style numbers, κ(S) (or respectively, κ*(S)) of S from the view-point of ergodic theory. Here κ(S) (κ* (S)) is the largest number of moving vectors (or respectively, conjugate-) of the differential system S that are mean linearly independent. For any ergodic measure v of S, two positive integers κ* (v) and κ(v), called the reduced and non-reduced style number of v respectively, are introduced. The connection between the style numbers of the system (M, S) and ones of the ergodic system (M, S; v) are discovered by the variational principle of style number proved in the paper. Several characterization theorems with respect to the style numbers κ* (S), κ*(v), κ(S) and κ(v) are presented respectively. [ABSTRACT FROM AUTHOR]

In this paper we study phase space relations in a certain class of discrete dynamical systems over graphs. The systems we investigate are called Sequential Dynamical Systems (SDSs), which are a class of dynamical systems that provide a framework for analyzing computer simulations. Specifically, an SDS consists of (i) a finite undirected graph Y with vertex set {1,2,…,n} where each vertex has associated a binary state, (ii) a collection of Y-local functions (Fi,Y)i∈v[Y] with $F_{i,Y}: \mathbb{F}_2^n\to \mathbb{F}_2^n$ and (iii) a permutation π of the vertices of Y. The SDS induced by (i)–(iii) is the map \[ [F_Y,\pi] = F_{\pi(n),Y} \circ \cdots \circ F_{\pi(1),Y}\,. \] The paper is motivated by a general reduction theorem for SDSs which guarantees the existence of a phase space embedding induced by a covering map between the base graphs of two SDSs. We use this theorem to obtain information about phase spaces of certain SDSs over binary hypercubes from the dynamics of SDSs over complete graphs. We also investigate covering maps over binary hypercubes, $Q_2^n$, and circular graphs, Circn. In particular we show that there exists a covering map $\phi: Q_2^n\to K_{n+1}$ if and only if 2n≡0 mod n+1. Furthermore, we provide an interpretation of a class of invertible SDSs over circle graphs as right-shifts of length n-2 over {0,1}2n-2. The paper concludes with a brief discussion of how we can extend a given covering map to a covering map over certain extended graphs. [ABSTRACT FROM AUTHOR]

In this paper, we study the asymptotic behavior of solutions to the cubic and the quadratic nonlinear Schrödinger equations in one and two space dimensions, respectively. When the nonlinearity is of a form f = |u|[sup p-1]u, it is known that there exist scattered states if p > 1+2/n and there does not otherwise. Therefore we may consider the nonlinearities treated in the present paper to be of critical order for the existence of scattered states though their forms differ slightly from that given above. We prove, however, that there exist scattered states for these critical nonlinear Schrödinger equations, in other words, that the wave operators exist on a certain set of final states. Our proof is mainly based on the construction of suitable approximate functions that approach to solutions of nonlinear Schrödinger equations at t = ∞. [ABSTRACT FROM AUTHOR]

An emulated digital CNN-UM (CASTLE) architecture was published few years ago.1 Different emulated digital CNN-UM architectures are analyzed in the paper. These new modified architectures are optimized according to the silicon area, operating speed or dissipated power. A reconfigurable arithmetic core will also be shown in the paper, by which solution of the neighborhood size can be changed. An advanced CASTLE with pipe-lining is presented. The operation frequency is increased by using this solution in approximately 10 times. [ABSTRACT FROM AUTHOR]

This paper considers a renewal process in which the interarrival times and rewards are characterized as fuzzy variables. A fuzzy elementary renewal theorem shows that the expected number of renewals per unit time is just the expected reciprocal of the interarrival time. Furthermore, the expected reward per unit time is provided by a fuzzy renewal reward theorem. Finally, a numerical example is presented for illustrating the theorems introduced in the paper. [ABSTRACT FROM AUTHOR]

In this paper we prove certain Hurwitz equivalence properties of B[sub n]. In particular we prove that for n = 3 every two Artin factorizations of [formula] of the form H[sub i[sub 1]] ⋯ H[sub i[sub 6]], F[sub j[sub 1]] ⋯ F[sub j[sub 6]] (with i[sub k], j[sub k] ∈ {1, 2}) where {H[sub 1], H[sub 2]}, {F[sub 1], F[sub 2]} are frames, are Hurwitz equivalent. The proof provided here is geometric, based on a newly defined frame type. The results will be applied to the classification of algebraic surfaces up to deformation. It is already known that there exist surfaces that are diffeomorphic to each other but are not deformations of each other (Manetti's example). We construct a new invariant based on Hurwitz equivalence of factorizations, to distinguish among diffeomorphic surfaces which are not deformation of each other. The main result of this paper will help us to compute the new invariant. [ABSTRACT FROM AUTHOR]

In this paper, a new computation system is defined by coupling a finite automaton with a deterministic Turing machine with one head and one tape that is infinite in one direction only. In a first part of the paper, it is shown that there is a Turing machine with five instructions for which it is possible to devise a finite automaton such that the resulting computation is able to simulate any Turing machine. In a second part of the paper it is shown that if the Turing machine has at most four instructions, whatever the finite automaton is, the halting of the resulting computation is always decidable. [ABSTRACT FROM AUTHOR]

This paper is concerned with a higher dimensional generalization of the main result of our previous paper [2] : we shall prove that the Poincaré metric on the leaves of a one-dimensional holomorphic foliation on a compact Kahler manifold has a plurisubharmonic variation. [ABSTRACT FROM AUTHOR]

The structure of groups in which many subgroups have a certain property χ has been investigated for several choices of the property χ. In particular, groups whose non-normal subgroups are supersoluble are studied in this paper. Moreover, groups with only finitely many normalizers of non-supersoluble groups are considered. [ABSTRACT FROM AUTHOR]

A two-valued function defined on the vertices of a graph , is a majority dominating function if the sum of its function values over at least half the closed neighborhoods is at least one. That is, for at least half the vertices , , where consists of and every vertex adjacent to . The majority domination number of a graph , denoted , is the minimum value of over all majority dominating functions of . The majority reinforcement number of , denoted by , is defined to be the minimum cardinality of a set of edges such that . In this paper, we initiate the study of majority reinforcement number and determine the exact values of for paths and cycles. [ABSTRACT FROM AUTHOR]

Fix , let be the loop Lie algebra over with basis and relations , where . In this paper, a formal distribution Lie algebra of is constructed. Then the associated conformal algebra is studied, where has a -basis with -brackets and . In particular, we determine the conformal derivations and rank one conformal modules of this conformal algebra. Finally, we study the central extensions and extensions of conformal modules. [ABSTRACT FROM AUTHOR]

In this paper, we consider the graded path category associated to a quiver. We investigate all n-differentials on such a category, and also study the associated graded Lie algebra. Moreover, a necessary and sufficient condition is given for the graded path category to admit a DG category structure. [ABSTRACT FROM AUTHOR]

An ideal I of a ring R is strongly separative provided that for all finitely generated projective R-modules A, B with A=AI and B=BI, if 2A ≅ A ⊕ B, then A ≅ B. We prove in this paper that a regular ideal I of a ring R is strongly separative if and only if each a ∈ 1+I satisfying (1-a)R ∝ r(a) is unit-regular, if and only if each a ∈ 1+I satisfying (1-a2)R ∝ r(a2) is unit-regular, if and only if each a ∈ 1+I satisfying R(1-a)R=R r(a) is unit-regular, if and only if each a ∈ 1+I satisfying R(1-a2)R=R r(a2) is unit-regular. [ABSTRACT FROM AUTHOR]

In this paper, we consider a class of non-weight modules for some algebras related to the Virasoro algebra: The algebra (a, b), the twisted deformative Schrödinger-Virasoro Lie algebras and the Schrödinger algebra. We study the modules whose restriction to the Cartan subalgebra (modulo center) are free of rank 1 for these algebras. Moreover, the simplicities of these modules are determined. [ABSTRACT FROM AUTHOR]

In the present paper, the σ-derivations of ℂ[x±1,y±1] are determined, and their applications are considered. [ABSTRACT FROM AUTHOR]

Uncertain differential system is a type of differential system involving uncertain processes. Stability analysis has been widely studied but no work has been dedicated to attractivity analysis of uncertain differential systems. In this paper, some concepts of attractivity for uncertain differential systems are presented. Then the corresponding sufficient and necessary conditions are given. Furthermore, the stability of the solutions and α-path of uncertain differential systems are studied. [ABSTRACT FROM AUTHOR]

In this paper, we consider a new class 풞(ϕ, ψ, η) of analytic functions defined by means of subordination. Coefficient bounds, Fekete-Szegö problem and norm estimates of the pre-Schwarzian derivatives of functions belonging to the class 풞(ϕ, ψ, η) are investigated. A class of multiple close-to-convex functions is also considered. [ABSTRACT FROM AUTHOR]

Let f : (ℝn, 0) → (ℝ, 0) be a nonconstant analytic function defined in a neighborhood of the origin 0 ∈ ℝn. The classical Łojasiewicz inequality states that there exist positive constants δ, c and l such that |f(x)| ≥ cd(x, f-1(0))l for |x| ≤ δ, where d(x, f-1(0)) denotes the distance from x to the set f-1(0). The Łojasiewicz exponent of f at the origin 0 ∈ ℝn, denoted by , is the infimum of the exponents l satisfying the Łojasiewicz inequality. In this paper, we establish a formula for computing the Łojasiewicz exponent of f in terms of the Newton polyhedron of f in the case where f is nonnegative and nondegenerate. [ABSTRACT FROM AUTHOR]

In this paper, the convolution sum Σi+25j=n σ(i)σ(j) is evaluated for all n ∈ ℕ based on some identities due to Berndt, Lemire and Williams. [ABSTRACT FROM AUTHOR]

Ramanujan's formula for the number r24(n) of representations of a positive integer n as a sum of 24 squares asserts that where and Ramanujan's function τ(n) is given by In this paper, we determine a class of formulae analogous to Ramanujan's formula for r24(n). [ABSTRACT FROM AUTHOR]

I trace the main steps of the first fifty-five years of my career as an applied mathematician, pausing from time to time to describe problems that arose in asymptotics and numerical analysis and had far-reaching effects on this career. Lecture delivered at Asymptotics and Applied Analysis, Conference in Honor of Frank W. J. Olver's 75th Birthday, January 10-14, 2000, San Diego State University, San Diego, California. Editors' Note: Frank W. J. Olver died on April 23, 2013. The following text was typed by his son, Peter J. Olver, from handwritten notes found among his papers. At times the writing is unpolished, including incomplete sentences, but the editors have decided to leave it essentially the way it was written. However, for clarity, some abbreviations have been written out in full. A couple of handwritten words could not be deciphered, and a guess for what was intended is enclosed in brackets: [...]. Endnotes have been made into footnotes within the body of the article. References were mostly not included in the handwritten text, but rather listed in order at the end. Citations to references have been included at the appropriate point in the text. [ABSTRACT FROM AUTHOR]

The unicyclic graph Cn,g obtained by appending a cycle Cg of length g to a pendent vertex of a path on n - g vertices is the lollipop graph on n vertices. In [Algebraic connectivity of lollipop graphs, Linear Algebra Appl.434 (2011) 2204–2210], Guo et al. proved that a(Cn,g-1) < a(Cn,g) for g ≥ 4, where a(Cn,g) is the algebraic connectivity of Cn,g. In this paper, we present a new approach which is quite different from that of Guo et al. in proving a(Cn,g-1) < a(Cn,g) for g ≥ 4. [ABSTRACT FROM AUTHOR]

In this paper, we study the derived categories of a Koszul algebra and its Yoneda algebra to determine when those categories are triangularly equivalent. We prove that the simply connected Koszul algebras are derived equivalent to their Yoneda algebras. We have considered discrete Koszul algebras and we gave necessary and sufficient conditions for those Koszul algebras to be derived equivalent to their Yoneda algebras. We also study the class of Koszul algebras which are derived equivalent to hereditary algebras. For the case where the hereditary algebra is tame, we characterized the derived equivalence between those Koszul algebras and their Yoneda algebras [ABSTRACT FROM AUTHOR]

A k-nacci (k-step Fibonacci) sequence in a finite group is a sequence of group elements x0, x1, x2, ..., xn, ... for which, given an initial (seed) set x0, x1, x2, ..., xj-1, each element is defined by From the definition, it is clear that the period of the k-nacci sequence in a group depends on the chosen generating set and the order in which the assignments of x0, x1, x2, ..., xj-1 are made. In this paper we examine the periods of the k-nacci sequences in the groups 픐2, and ℜ2, where each term of the sequence is reduced modulo 2. [ABSTRACT FROM AUTHOR]

As an extension of the basic model of MRA-codes, multi-receiver multi-fold authentication codes can use a single key distribution phase for multiple message transmission. A multi-receiver multi-fold authentication code is constructed from the singular symplectic geometry over finite fields in this paper. The parameters and probabilities of success in impersonation and substitution attacks by malicious groups of receivers of this code are computed. [ABSTRACT FROM AUTHOR]

The action of PSL(2,ℤ) on PL(F5n) yields PSL(2,5). In this paper, we use the adjacency matrices of the abstract group PSL(2,5), eventually of fullerene C60, to draw the coset diagram and investigate various properties of the diagram with reference to the intransitivity of the action and the number of orbits. [ABSTRACT FROM AUTHOR]

In this paper we mainly study sporadic groups in terms of p-local rank, especially, the 2-local ranks of some sporadic groups are given. [ABSTRACT FROM AUTHOR]

In this short paper, it is proved that every pair of large positive odd integers satisfying some necessary conditions can be represented in the form of a pair of one prime, two prime squares and k powers of 2. In particular, we have k -- 332. [ABSTRACT FROM AUTHOR]