4,945 research outputs found
First birth trends in developed countries
Levels and trends of various facets concerning first births are continuously changing. The evidence confirms that the postponement of first births is an ongoing and persisting process which started in western countries among cohorts of the 1940s, but only in the 1960s cohorts in Central and Eastern Europe. The mean age of women having first births is universally rising. Fertility of older women was increasing. The decline in childbearing of young women is robust among the cohorts of the late 1960s and the 1970s; in Southern Europe as well as in central and Eastern Europe the rates of decline have accelerated. Childbearing behavior in the formerly socialist countries is in transition to a different regime.changing age patterns, childlessness, cohort analysis, developed countries, first birth, postponement, transition to different age patterns in Central and Eastern Europe
ORDER-SORTED RIGID E-UNIFICATION
Rigid E-Unification is a special type of unification which arises naturally when
extending Andrew's method of matings to logic with equality. We study the rigid E-Unification
problem in the presence of subsorts. We present an order sorted method
for the computation of order sorted rigid-E-unifiers. The method is based on an unsorted
one which we refine and extend to handle sort information. Our approach is to
incorporate the sort information within the method so as to leverage it. We show via
examples how the order sorted method is able to detect failures due to sort conflicts
at an early stage in the construction of potential rigid E Unifiers. The algorithm presented
here is NP-complete, as is the unsorted one. This is significant, specially due to
the complications presented by the sort information.Information Systems Working Papers Serie
Extended Hermite Subdivision Schemes
International audienceSubdivision schemes are efficient tools for building curves and surfaces. For vector subdivision schemes, it is not so straightforward to prove more than the Hölder regularity of the limit function. On the other hand, Hermite subdivision schemes produce function vectors that consist of derivatives of a certain function, so that the notion of convergence automatically includes regularity of the limit. In this paper, we establish an equivalence betweena spectral condition and operator factorizations, then we study how such schemes with smooth limit functions can be extended into ones with higher regularity. We conclude by pointing out this new approach applied to cardinal splines
From Hermite to stationary subdivision schemes in one and several variables
International audienceVector and Hermite subdivision schemes both act on vector data, but since the latter one interprets the vectors as function values and consecutive derivatives they differ by the "renormalization" of the Hermite scheme in any step. In this paper we give an algebraic factorization method in one and several variables to relate any Hermite subdivision scheme that satisfies the so-called spectral condition to a vector subdivision scheme. These factorizations are natural extensions of the "zero at π" condition known for the masks of refinable functions. Moreover, we show how this factorization can be used to investigate different forms of convergence of the Hermite scheme and why the multivariate situation is conceptionally more intricate than the univariate one. Finally, we give some examples of such factorizations
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