The algebra of basic covers of a graph G, denoted by Ā(G), was introduced by Herzog as a suitable quotient of the vertex cover algebra. In this paper we compute the Krull dimension of Ā(G) in terms of the combinatorics of G. As a consequence, we get new upper bounds on the arithmetical rank of monomial ideals of pure codimension 2. Furthermore, we show that if the graph is bipartite, then Ā(G) ...

Proof. Proof of claim 1: Suppose all agents acquire full information. In this case Π(bi) = 0 and each agent has to pay c. Deviating from the equilibrium means that the agent receives an uninformative signal, i.e. bi → ∞, but does not have to pay c. From the definition we can easily see that as bi → ∞, τv → 0. In the full information equilibrium, the agent knows that ā = s and thus Var [ā|Ii] = ...

Abstract In this paper we introduce a new family Ā(α, β, γ) of harmonic univalent functions with negative coefficients using fractional calculus operator Ωλwhich contains various well known classes of harmonic univalent functions as well as many new ones. We obtain coefficient estimate, distortion theorem and various other properties for functions belonging to the class Ā(α, β, γ) in the unit d...

We study equilibrium configurations of thin and elongated non-Euclidean elastic strips with hyperbolic two-dimensional reference metrics ā which are invariant along the strip. In the vanishing thickness limit energy minima are obtained by minimizing the integral of the mean curvature squared among all isometric embeddings of ā. For narrow strips these minima are very close to minimal surfaces r...

G = H⊕M, [H,H] ⊂ H, [H,M] ⊂ M. (3) There are different methods of studying correlation functions of gaugedWZNWmodels such as the free field realization approach or the fermionization technik [2]. We shall pursue a different idea which is paralell to the analysis of the gravitational dressing of 2D field theories [3]. Our starting point are the equations of motion of the gauged WZNW model: ∇̄(∇gg...

A stream is an infinite sequence of data from a set A. A wide variety of algorithms and architectures operate continuously in time, producing streams of data, for example: systolic arrays, data-flow machines, neural networks and cellular automata. Also many models of real number computation use streams. In this paper we study the construction of an algebra Ā of streams over a many-sorted algebr...

We examine finite words over an alphabet Γ = {a, ā; b, b̄} of pairs of letters, where each word w1w2...wt is identified with its reverse complement w̄t...w̄2w̄1 (where ā = a, b̄ = b). We seek the smallest k such that every word of length n, composed from Γ, is uniquely ∗This work was supported, in part, by Hungarian NSF, under contract Nos. AT48826, NK62321, F043772, N34040, T34702, T37846, T43758, ...

We consider the nonlinear beam equation utt + a(x)ut − f(ux)x + uxxxx = 0 in a bounded interval (0, 1) ⊂ R. The equation has an indefinite damping term, i.e., with a damping function a = a(x) possibly changing sign. For this non-dissipative situation we prove the exponential stability of the corresponding linearized system provided ā = ∫ 1 0 a(x)dx > 0 and ‖ a− ā ‖L2≤ τ , for τ small enough. We...