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Let Q denote the field of rational numbers, and let p be an odd prime number. Let K be a cyclic extension of Q of degree p, and let a be a generator of Gal (KQ). Let CK denote the p-class group of K (i.e., the Sylow p-subgroup of the ideal class group of K), and let for i = 1, 2, 3, . It is well known that is an elementary abelian p-group of rank tt1, where t is the number of ramified primes in KQ. So we focus our attention on . We let
A high Reynolds number theory is developed for a viscous fluid flowing through an elastic channel. Unlike the flow through rigid symmetric channels, the viscous flow through a symmetric elastic channel is found to admit free-interaction solutions, due solely to the interaction of the boundary layer with the elastic channel wall. The assumption of symmetry is found to be general providing that the streamwise extent of the channel collapse dilation is larger than O(K17) and the channel is allowed to deviate only slightly from a straight channel. These free-interactions are believed to be the viscous initiation of a sudden collapse or dilation of the channel, commonly observed in experiment. The collapse of the channel is found to occur over a wide range of possible streamwise length scales from O(l) to O(K). For a rigid channel which is coated with a thin elastic solid, the equations are found to reduce to the hypersonic strong interaction problem of triple-deck theory. The hypersonic triple-deck is known to admit both compressive and expansive free-interactions. The expansive free-interaction is found to correspond to a sudden collapse of the channel and an acceleration of the flow within the core of the channel. A cha nnel that is backed by a stagnant constant pressure fluid is also examined. For this problem, the pressure is proportional to the negativeof the fourth derivative of the channel wall displacement. This structure is also found to admit compressive andor expansive free-interactions, depending on whether the internal pressure within the channel is less than or greater than the constant pressure external to the channel. Terminal forms are developed for the expansive free-interaction and compared with numerical calculations.
Filters and אּ-complete filters can be used to produce set-theoretic extensions of direct sums and direct products. They can be applied to generalize theorems in module theory which involve these. For example, the theorem, stating that a ring is noetherian, if, and only if, direct sums of injectives are injective, can be generalized, provided we replace noetherian by Xa-noetherian and direct sums by אּ- complete filter sums with a suitable property.
The existence of inductive limits in the category of (topological) measure spaces is proved. Next, permanence properties of inductive limits are investigated. If (X, , ) is the inductive limit of the measure spaces (X, , ), we prove, for 1 p 221E;, that LP(X, , ) is embeddible into the projectilimit of Lp(X, ,) in the category Ban, for p <, respectively in the category C* in the case p = +. As an application, we exten existence theorems of strong liftings to inductive limits.
We begin by denning the notion of a tangential limit for a function f denned in the unit disc
Let be a positive continuous function on (0, 1) for which
Suppose B>0, -,and define
where The region . makes tangential contact with the boundary U of the unit disc at ei; when (r) = ( l - r2), for instance, (, , 1) is the disc with radiusand centre ei
This study extends earlier work on the characterization of the asymmetry of a section of a typical three-dimensional Brownian path using the moment of inertia tensor about the centre of mass. A new method for determining an upper bound on the ensemble average of the smallest eigenvalue is presented. This work has applications to polymer science, since single chain polymer molecules are often modelled as sections of Brownian paths.
As the size of the bibliography (which contains only a fraction of the existing literature on functional equations) indicates, it would be hopeless to try to present in one chapter of this book an even approximately complete history of functional equations (in several variables). So we restrict ourselves to a few notes (cf. also Aczél 1966c, pp. 5–12; Dhombres 1986) on the beginnings of this part of mathematics, some milestones in its development and a sketchy panorama of its present aspirations and applications.
Definition of linear and quadratic functions by functional equations in the Middle Ages and application of an implied characterization by Galileo
The emergence of functional equations was necessarily connected to the development of the notion of function, but we cannot, of course, go into the details of that history here. Because of the absence of any notion of function it would be very contrived to interpret passages of Euclid or Archimedes as even disguised formulations of functional equations. One should also differentiate between stating, for given functions, properties which amount to functional equations satisfied by them, and determining all functions with such properties, that is, solving these functional equations.
An important historical role of functional equations has been the definition of functions by functional equations (or their paraphrases). But often it was not shown (though it was implied) that these functions are the only solutions of these equations.