In this paper, we consider the second-order nonlinear and the nonlinear neutral functional differential equations (a(t)x′(t))′ + f(t, x(g(t))) = 0, t ≥ t0 (a(t)(x(t)− p(t)x(t− τ))′)′ + f(t, x(g(t))) = 0, t ≥ t0 . Using the Banach contraction mapping principle, we obtain the existence of throughout positive solutions for the above equations.

Streams, or infinite lists, have many applications in functional programming, and are naturally defined using recursive equations. But how do we ensure that such equations make sense, i.e. that they actually produce well-defined streams? In this article we present a new approach to this problem, based upon the topological notion of contractive functions on streams. In particular, we give a soun...

We derive a uniform bound for the difference of two contractive semigroups, if the difference of their generators is form-bounded by the Hermitian parts of the generators themselves. We construct a semigroup dynamics for second order systems with fairly general operator coefficients and apply our bound to the perturbation of the damping term. The result is illustrated on a dissipative wave equa...

Streams, or infinite lists, have many applications in functional programming, and are naturally defined using recursive equations. But how do we ensure that such equations make sense, i.e. that they actually produce well-defined streams? In this article we present a new approach to this problem, based upon the topological notion of contractive functions on streams. In particular, we give a soun...

We prove the existence of common fixed points of a sequence of multivalued mappings satisfying Edelstein type contractive condition. As an application, common fixed points of a sequence of single valued expansive type mappings have been obtained. © 2008 Elsevier Ltd. All rights reserved.

* Correspondence: poom. [email protected] Department of Mathematics, Faculty of Science, King Mongkut’s University of Technology Thonburi (KMUTT), Bangmod, Bangkok 10140, Thailand Abstract In this article, we study and prove the new existence theorems of fixed points for contraction mappings in modular metric spaces. AMS: 47H09; 47H10.

Consider two agents who learn the value of an unknown parameter by observing a sequence of private signals. The signals are independent and identically distributed across time but not necessarily across agents. We show that that when each agent’s signal space is finite, the agents will commonly learn its value, i.e., that the true value of the parameter will become approximate common-knowledge....

The aim of this paper is to study the solvability of the Dirichlet problem for certain types of fully nonlinear elliptic equations. The theory of weakly-near operators, combined to Contraction Mapping and Schauder fixed point theorems, is used. Our main results generalizes similar ones given by S. Campanato and A. Tarsia.

Increasing sequences of contractive projections on a reflexive LP space share an unconditionality property similar to that exhibited sequences of self-adjoint projections on a Hilbert space. A slight variation of this property is shown to be precisely the correct condition on a reflexive Banach space to ensure that every operator with a contractive AC-functional calculus is scalar-type spectraL