1,720,977 research outputs found
Dichotomies for evolution equations in Banach spaces
No full textThe aim of this paper is to emphasize various concepts of dichotomies for evolution equations in Banach spaces, due to the important role they play in the approach of stable, instable and central manifolds. The asymptotic properties of the solutions of the evolution equations are studied by means of the asymptotic behaviors for skew-evolution semiflows
On polynomial stability for skew-evolution semiflows on Banach spaces
No full textMany of the processes that arise in engineering, physics or economics can be described by mathematical models that imply nonlinear evolution equations. Of great interest is, as we emphasize in this paper, to study the study the solutions of differential equations using an original concept, the skew-evolution semiflows, which generalize the classic notions of evolution operators and skew-product semiflows. The techniques from the domain of nonautonomous equations in infinite dimensions with unbounded coefficients are extended for the study of the above categories. The main concern of this paper is to give definitions, examples, connections and characterizations for various concepts for the asymptotic properties of stability of solutions for evolution equations in a nonuniform setting
Exponential Dichotomy and Trichotomy for Skew-Evolution Semiflows in Banach Spaces
No full textThe paper emphasizes the properties of exponential dichotomy and exponential trichotomy for skew-evolution semiflows in Banach spaces, by means of evolution semiflows and evolution cocycles. The approach is from uniform point of view. Some characterizations which generalize classic results are also provided
On Exponential Stability for Skew-Evolution Semiflows on Banach Spaces
No full textThe paper emphasizes the property of stability for skew-evolution semiflows on Banach spaces, defined by means of evolution semiflows and evolution cocycles and which generalize the concept introduced by us in a previous paper. There are presented several general characterizations of this asymptotic property out of which can be deduced well known results of the stability theory. A unified treatment in the uniform and in the nonuniform setting is given. The main results are also formulated in discrete time
On Exponential Stability for Skew-Evolution Semiflows on Banach Spaces
No full textThe paper emphasizes the property of stability for skew-evolution semiflows on Banach spaces, defined by means of evolution semiflows and evolution cocycles and which generalize the concept introduced by us in a previous paper. There are presented several general characterizations of this asymptotic property out of which can be deduced well known results of the stability theory. A unified treatment in the uniform and in the nonuniform setting is given. The main results are also formulated in discrete time
Pointwise Trichotomy for Skew-Evolution Semiflows on Banach Spaces
No full textThe paper introduces the notion of skew-evolution semiflows and presents the concept of pointwise trichotomy in the case of skew-evolution semiflows on a Banach space. The connection with the classic notion of trichotomy presented by us in a previous paper in 2006 for evolution operators, is also emphasized, as well as some characterizations. The approach of the theory is from uniform point of view. The study can also be extended to systems with control whose state evolution can be described by skew-evolution semiflows
Exponential Dichotomy and Trichotomy for Skew-Evolution Semiflows in Banach Spaces
No full textThe paper emphasizes the properties of exponential dichotomy and exponential trichotomy for skew-evolution semiflows in Banach spaces, by means of evolution semiflows and evolution cocycles. The approach is from uniform point of view. Some characterizations which generalize classic results are also provided
Pointwise Trichotomy for Skew-Evolution Semiflows on Banach Spaces
No full textThe paper introduces the notion of skew-evolution semiflows and presents the concept of pointwise trichotomy in the case of skew-evolution semiflows on a Banach space. The connection with the classic notion of trichotomy presented by us in a previous paper in 2006 for evolution operators, is also emphasized, as well as some characterizations. The approach of the theory is from uniform point of view. The study can also be extended to systems with control whose state evolution can be described by skew-evolution semiflows
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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