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          <dc:title>Constructive Proofs or Constructive Statements?</dc:title>
          <dc:creator>Rubio Garcia, Julio</dc:creator>
          <dc:subject>Program extraction</dc:subject>
          <dc:subject>symbolic computation</dc:subject>
          <dc:subject>constructive logic</dc:subject>
          <dc:description>A question raised at previous MAP meetings is&#13;
the following. Is Sergeraert's "Constructive &#13;
Algebraic Topology" (CAT, in short) really&#13;
constructive (in the strict logical sense of the&#13;
word "constructive")? We have not an answer to&#13;
that question, but we are interested in the&#13;
following: could have a positive (or negative)&#13;
answer to the previous question an influence in&#13;
the problem of proving the correctness of CAT&#13;
programs (as Kenzo)?&#13;
&#13;
&#13;
Studying this problem, we have observed that, in&#13;
fact, many CAT programs can be extracted from&#13;
the statements (that is, from the specification&#13;
of certain objects and constructions), without&#13;
needing an extraction from proofs. This remark&#13;
shows that the logic used in the proofs is&#13;
uncoupled with respect to the correctness of&#13;
programs. Thus, the first question posed could&#13;
be quite irrelevant from the practical point of&#13;
view. These rather speculative ideas will be&#13;
illustrated by means of some elementary&#13;
examples, where the Isabelle code extraction&#13;
tool can be successfully applied.</dc:description>
          <dc:publisher>Schloss Dagstuhl – Leibniz-Zentrum für Informatik</dc:publisher>
          <dc:contributor>Julio Rubio Garcia</dc:contributor>
          <dc:date>2006</dc:date>
          <dc:relation>Is Part Of Dagstuhl Seminar Proceedings, Volume 5021, Mathematics, Algorithms, Proofs (2006)</dc:relation>
          <dc:type>InProceedings</dc:type>
          <dc:type>Text</dc:type>
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          <dc:identifier>doi:10.4230/DagSemProc.05021.10</dc:identifier>
          <dc:identifier>urn:nbn:de:0030-drops-2894</dc:identifier>
          <dc:identifier>https://drops.dagstuhl.de/entities/document/10.4230/DagSemProc.05021.10</dc:identifier>
          <dc:language>eng</dc:language>
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