皆様
National Chung-Cheng UniversityのHsing-chien Tsai先生の講演のお知らせです。どうぞふるってご参加ください。
問合せ先:
佐野勝彦
北陸先端科学技術大学院大学 情報科学研究科
e-mail: v-sano(a)jaist.ac.jp
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* JAIST Logic Seminar Series *
Date and Time: Tuesday, 6th October 2015, 15:30--17:00
Title: On Some General Methods of Proving Decidability or Undecidability
Place: Collaboration room No.7, 5th floor of IS building No. 3, JAIST
(Access: http://www.jaist.ac.jp/english/location/access.html)
Speaker: Hsing-chien Tsai (Department of Philosophy, National
Chung-Cheng University)
Abstract: This talk will first introduce some useful general methods
of proving the decidability or the undecidability of a first-order
logical theory, and then will show some applications of those methods.
The methods to be looked into are heavily involved with checking
whether or not two models (or two classes of models) stand in certain
relations. Here the two most-checked relations between two models are
back-and-forth equivalence and definability (that is, defining one
into another). In this light, this talk will also briefly discuss some
general theorems concerning the two aforementioned model theoretical
relations.
--
Katsuhiko Sano
School of Information Science
Japan Advanced Institute of Science and Technology
IS building No.1 7F, 1-1 Asahidai,
Nomi, Ishikawa, 923-1292, Japan
皆様
ジーゲン大学のDieter Spreen先生の講演のお知らせです。
どうぞふるってご参加ください。
問合せ先:
石原 哉
北陸先端科学技術大学院大学 情報科学研究科
e-mail: ishihara(a)jaist.ac.jp
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* JAIST Logic Seminar Series *
* This seminar is held as a part of JSPS Core-to-Core Program,
A. Advanced Research Networks, and EU FP7 Marie Curie Actions
IRSES project COMPUTAL (http://computal.uni-trier.de/).
Date: Thursday 7 May, 2015, 13:30-15:00
Place: JAIST, Collaboration room 6 (I-57g)
(Access: http://www.jaist.ac.jp/english/location/access.html)
Speaker: Dieter Spreen (University of Siegen)
Title: Digit Spaces - Topological Foundations
Abstract:
Digit spaces have been introduced by Ulrich Berger as a framework for
extracting programs that deal with continuous data from formal proofs.
The essential idea was to represent objects as streams of unary
contractions on a complete metric space and to use coinduction on the
logical side.
In recent joint work on an extension of this approach to hyperspaces
like the space of nonempty compact subsets of a digit space,
it turned out that compact cannot be represented by such streams in
general: instead one has to deal with infinite trees the nodes of which
are labeled by
contraction similar to the stream case.
It was realized, however, that one will obtain a uniform theory, if the
contractions, also called digits, are allowed to be multi-ary.