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{\LARGE \bf Geometric Modelling and CAD}
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{\bf Organizers}
\begin{itemize}
\item
J. Rafael Sendra (mtsendra@alcala.es)


\item
Sabine Stifter (Sabine.Stifter@risc.uni-linz.ac.at)

\end{itemize}
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{\bf Description}
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Recently, algorithmic techniques from Computer Algebra and Constructive Methods in Algebraic
Geometry have been applied successfully in Geometric Modelling and in Computer Aided
Geometric Design. This session focusses on some fundamental algorithmic tecniques (as Stright
Line Programs, Gr\"obner Basis), as well as conversion algorithms for curves and surfaces (as
parametrizations and implicitizations). Also applications to parametrization of envelopes and
unirationality analisys of offset varieties are treated. 

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{\bf Talks}
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Date: July 18th (Thursday) 

\begin{description}
\item[8:30-8:55] \ \\
  Franz Winkler\\
  {\bf Parametrization over prescribed coefficient fields.
} 
\item[8:55-9:20] \ \\
  Hoon Hong, Josef Schicho
\\
  {\bf Implicitization of Nested Circular Curves and generalizations.
} 
\item[9:20-9:45] \ \\
  Helmut Pottmann, Martin Peternell
\\
  {\bf Rational Parametrizations for Envelopes of Natural Quadrics.
} 
\item[9:45-10:10] \ \\
  E. Arrondo, J. Sendra, J.R. Sendra\\
  {\bf Unirational Generalized Offset to Hypersurfaces.
} 
\item[10:10-10:45] \ \\
  \\
  {\bf Coffee Break 
} 
\item[10:45-11:10] \ \\
  M. Giusti, K. H\"agele, J. Heintz, J.E. Morais, J.L. Monta\~na, L.M. Pardo
\\
  {\bf Lower Bounds for Diophantine Approximations.
} 
\item[11:10-11:35] \ \\
  Thomas Sauer\\
  {\bf Constructing Gr\"obner Basis by Interpolation.
} 
\end{description}

