A general Galois theory for dual operations and dual relations
A general Galois theory for dual operations and dual relations
A general Galois theory for dual operations and dual relations
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If all finite copowers of X are finite (which happens in most of the usual categories<br />
as soon as X is finite), we have Loc F = F <strong>and</strong> LOC R = R <strong>for</strong> all F ⊆ OX<br />
<strong>and</strong> R ⊆ RX. Thus, in this case, the <strong>Galois</strong> closed sets are exactly the clones of<br />
<strong>dual</strong> <strong>operations</strong> <strong>and</strong> the clones of <strong>dual</strong> <strong>relations</strong>, respectively.<br />
We end the talk with discussing possible applications of this <strong>theory</strong>.<br />
References<br />
[1] Csákány B. : Completeness in coalgebras, Acta Sci. Mat.48 (1985), pp. 75-84.<br />
[2] Maˇsulović D. : On <strong>dual</strong>izing clones as Lawvere theories, International Journal of Algebra<br />
<strong>and</strong> Computation 16 (2006), pp. 675-687.<br />
[3] Pöschel R., Kaluˇznin L.A. : Funktionen- und Relationenalgebren, Deutscher Verl. der Wiss.,<br />
Berlin, 1979.<br />
[4] Pöschel R. : Concrete representation of algebraic structures <strong>and</strong> a <strong>general</strong> <strong>Galois</strong> <strong>theory</strong>,<br />
in: Contributions to General Algebras, Proc. Klagenfurt Conf., May 1978, Verlag J. Heyn,<br />
Klagenfurt, Austria, 1979, pp. 249-272.<br />
[5] Pöschel R., Rössiger M., A <strong>general</strong> <strong>Galois</strong> <strong>theory</strong> <strong>for</strong> cofunctions <strong>and</strong> co<strong>relations</strong>, Algebra<br />
universalis 43 (2000), pp. 331-345.<br />
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