In this paper we establish existence and regularity of positive solutions for a singular quasilinear elliptic system with competitive structure. The approach is based on comparison properties, a priori estimates and the Schauder’s …xed point theorem.

We establish a xed point theorem for a certain type of nonexpanding maps in Euclidean buildings, which is inspired by a theorem of La aille in p-adic Hodge theory [7, Theorem 3.2].

|Bifurcations of periodic orbits are studied for two-dimensional diieomorphisms close to a diieomorphism with the quadratic homoclinic tangency to a saddle xed point whose Jacobian is equal to one. Problems of the coexistence of periodic orbits of various types of stability are considered. INTRODUCTION It is well known that homoclinic bifurcations of two-dimensional diieomorphisms generally giv...

G. Gaeta Department of Mathematics, Loughborough University, Loughborough LE11 3TU (G.B.) [email protected] G. Marmo Dipartimento di Scienze Fisiche, Universit a di Napoli, and INFN, Sezione di Napoli, 80123 Napoli (Italy) Summary. We consider the classical problem of linearizing a vector eld X around a xed point. We adopt a nonperturbative point of view, based on the symmetry properties of lin...

Fixed-order computation rules, used by Prolog and most deductive database systems, do not suuce to compute the well-founded semantics 29] because they cannot properly resolve loops through negation. This inadequacy is reeected both in formulations of SLS-resolution 17, 23] which is an ideal search strategy, and in more practical strategies like SLG 5], or Well-Founded Ordered Search 27]. Typica...

We develop a model-checking algorithm for a logic that permits propositions to be deened using greatest and least xed points of mutually recursive systems of equations. This logic is as expressive as the alternation-free fragment of the modal mu-calculus identiied by Emerson and Lei, and it may therefore be used to encode a number of temporal logics and behavioral preorders. Our algorithm deter...

Results are obtained concerning the distribution of ranked relative lengths of excursions of a recurrent Markov process from a point in its state space whose inverse local time process is a stable subordinator. It is shown that for a large class of random times T the distribution of relative excursion lengths prior to T is the same as if T were a xed time. It follows that the generalized arc-si...

Hybrid systems combine discrete and continuous behavior. We study properties of trajectories of a rectangular hybrid system in which the discrete state goes through a loop. This system is viable if there exists an innnite trajectory starting from some state. We show that the system is viable if and only if it has a limit cycle or xed point. The set of xed points is a polyhedron. The viability k...

horizon map Representing the Visibility Structure of a Polyhedral Terrain through a Horizon Map We present a model for describing the visibility of a polyhedral terrain from a xed viewpoint, based on a collection of nested horizons. We brie y introduce the concepts of mathematical and digital terrain models, and some background notions for visibility problems on terrains. Then, we de ne horizon...

This paper deals with cocycles over ergodic metric dynamical systems with values in the semi-direct product of Z 2 and R. We show that such cocycles are recurrent under very general assumptions. Furthermore, we give criteria for the existence of invariant measures for group valued cocycles. With that, examples of continuous random dynamical systems on a compact interval without random xed point...