         Better Answers to Real Questions
         Marek Košta1 , Thomas Sturm1 and Andreas Dolzmann2
           1
               Max-Planck-Institut für Informatik, 66123 Saarbrücken, Germany
                      mkosta@mpi-inf.mpg.de, sturm@mpi-inf.mpg.de
               2
                 Leibniz-Zentrum für Informatik, 66041 Saarbrücken, Germany
                              andreas.dolzmann@dagstuhl.de

                                         Abstract
    We consider existential problems over the reals. Extended quantifier elimination gener-
alizes the concept of regular quantifier elimination by providing in addition answers, which
are descriptions of possible assignments for the quantified variables. Implementations of
extended quantifier elimination via virtual substitution have been successfully applied to
various problems in science and engineering. So far, the answers produced by these im-
plementations included infinitesimal and infinite numbers, which are hard to interpret in
practice. We introduce here a post-processing procedure to convert, for fixed parameters,
all answers into standard real numbers. The relevance of our procedure is demonstrated
by applications of our implementation to various examples from the literature, where it
significantly improves the quality of the results.