Configurations in Coproducts of Priestley Spaces

نویسندگان

  • Richard N. Ball
  • Ales Pultr
  • Jirí Sichler
چکیده

Let P be a configuration, i.e., a finite poset with top element. Let Forb(P ) be the class of bounded distributive lattices L whose Priestley space P(L) contains no copy of P . We show that the following are equivalent: Forb(P ) is first-order definable, i.e., there is a set of first-order sentences in the language of bounded lattice theory whose satisfaction characterizes membership in Forb(P ); P is coproductive, i.e., P embeds in a coproduct of Priestley spaces iff it embeds in one of the summands; P is a tree. In the restricted context of Heyting algebras, these conditions are also equivalent to ForbH(P ) being a variety, or even a quasivariety.

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عنوان ژورنال:
  • Applied Categorical Structures

دوره 13  شماره 

صفحات  -

تاریخ انتشار 2005