A projective algebraic surface which is homeomorphic to a ruled surface over a curve of genus g ≥ 1 is itself a ruled surface over a curve of genus g. In this note, we prove the analogous result for projective algebr...
A projective algebraic surface which is homeomorphic to a ruled surface over a curve of genus g ≥ 1 is itself a ruled surface over a curve of genus g. In this note, we prove the analogous result for projective algebraic manifolds of dimension 4 in the case g ≥ 2.
Gröbner bases are useful for analysing multivariate polynomial ideals. For different coefficient domains R , it is shown how to construct (weak) Gröbner bases using bases of modules of syzygies, and under co...
Gröbner bases are useful for analysing multivariate polynomial ideals. For different coefficient domains R , it is shown how to construct (weak) Gröbner bases using bases of modules of syzygies, and under constructibility conditions on R an algorithm for finding the required module bases is given. These methods are described in detail for principal ideal rings R . This leads to strong Gröbner bases and in case of fields R the construction is the known Buchberger algorithm.
We determine the Hilbert function of a determinantal ring and of its canonical module using a combinatorial result of Krattenthaler. This gives a new proof of Abhyankar's formula.
We determine the Hilbert function of a determinantal ring and of its canonical module using a combinatorial result of Krattenthaler. This gives a new proof of Abhyankar's formula.
We introduce non-autonomous well-posed and (absolutely) regular linear systems as quadrupels consisting of an evolution family and output, input and input-output maps subject to natural hypotheses. In the spirit of G....
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As part of the multi-million Euro "Notebook University Project" in Germany, we investigate new ways in which students access instructional material and how they interact with it. The ultimate goal is to bett...
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ISBN:
(纸本)088986361X
As part of the multi-million Euro "Notebook University Project" in Germany, we investigate new ways in which students access instructional material and how they interact with it. The ultimate goal is to better support the cognitive process of turning the abundance of explicit knowledge into useful implicit (tactile) knowledge. We argue that carrying explicit information around, e.g. in form of a notebook, is an obsolete approach in the age of networking. We suggest, as large size displays and input devices become freely available in many locations on and off campus, it is sufficient to connect to them via a remote control which could be a PDA or a mobile phone (which in the future will be one and the same anyway). This paper illustrates some of the architectural requirements, identifies desirable interaction conventions and proposes suitable changes to our educational practices.
The main algorithmic techniques that have been proposed for XPath Query Containment are described. It is shown that XPath expressions can be evaluated in polynomial time. The XPath fragments are characterized in terms...
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The main algorithmic techniques that have been proposed for XPath Query Containment are described. It is shown that XPath expressions can be evaluated in polynomial time. The XPath fragments are characterized in terms of existential first-order logic. It is suggested that the inclusion structure of the XPath expressions should be computed in advance to decrease online computation time.
The Knuth-Bendix completion procedure is a tool for algorithmically completing term rewriting systems which are operationally incomplete in the sense that the uniqueness of normal forms is not guaranteed. As the probl...
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We define semantic overlapping as the description of different points of view on the same application context in different parts of a database schema. E. g. type definitions may refer to each other and include the def...
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作者：
Karlsen, Einar W.TZI
FB3 Mathematik und Informatik Universität Bremen Germany
The UniForM Workbench is an open ended tool integration framework for developing (formal) Software Development Environments (SDE) from the basis of prefabricated off-the-shelf development tools. The integration framew...
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