Women are fecund for a shorter period of their lives than men. This paper investigates how di erential fecundity interacts with marriage, labor and nancial markets to a ect gender roles. The main ndings of the paper are: (i) Di erential fecundity does not have any market invariant gender e ect. (ii) Gender roles depend on competition for mates in the marriage market and the way in which ex-post...

Although traditional scale-space theory provides a well-founded framework for dealing with image structures at di erent scales, it does not directly address the problem of how to select appropriate scales for further analysis. This paper introduces a new tool for dealing with this problem. A heuristic principle is proposed stating that local extrema over scales of di erent combinations of norma...

We present alternative algorithms for computing symmetric powers of linear ordinary diierential operators. Our algorithms are applicable to operators with coeecients in arbitrary integral domains and become faster than the traditional methods for symmetric powers of suuciently large order, or over suuciently complicated coeecient domains. The basic ideas are also applicable to other computation...

An initial value problem for y0 = f(t; y) may have an associated event function g(t; y). An event is said to occur at t when g(t ; y(t )) = 0. We consider problems for which the de nition of f(t; y) changes at the time of an event. A number of solvers locate events and restart the integration there so as to deal with the changes in f , but there is little theoretical support for what is done. H...

An action system framework is a predicate transformer based method for modelling and analysing distributed and reactive systems. The actions are statements in Dijkstra's guarded command language, and their semantics is given by predicate transformers. We extend conventional action systems with a di erential action consisting of a di erential equation and an evolution guard. The semantics is giv...

A vector …eld in n-space is reconstructed from a n-dimensional family of ray or line integrals. A similar problem is considered for di¤erential forms of higher order. Key words: Di¤erential form, ray integral, k-plane integral, reconstruction, support condition AMS subject classi…cation (2000): Primary, 53C65; Secondary, 65R32, 76M27 Abbreviated title: Doppler transform 1 Introduction Integrals...

The main topics of this technical report are quaternions, their mathematical properties, and how they can be used to rotate objects. We introduce quaternion mathematics and discuss why quaternions are a better choice for implementing rotation than the well-known matrix implementations. We then treat di erent methods for interpolation between series of rotations. During this treatment we give co...

in this paper, the convergence of zakharov-kuznetsov (zk) equation by homo- topy analysis method (ham) is investigated. a theorem is proved to guarantee the conver- gence of ham and to nd the series solution of this equation via a reliable algorithm.

generalized solution on neumann problem of the fourth order ordinary dierential equation in space w2 (0; b) has been discussed , we obtain the condition on b.v.p when the solution is in classical form. formulation of quintic spline function has been derived and the consistency relations are given.numerical method,based on quintic spline approximation has been developed. spline solution of the...

in this paper, we prove the existence of the solution for boundary value prob-lem(bvp) of fractional dierential equations of order q 2 (2; 3]. the kras-noselskii's xed point theorem is applied to establish the results. in addition,we give an detailed example to demonstrate the main result.