Configurations in Coproducts of Priestley Spaces
نویسندگان
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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ورودعنوان ژورنال:
- Applied Categorical Structures
دوره 13 شماره
صفحات -
تاریخ انتشار 2005