Automorphisms and strongly invariant relations
نویسندگان
چکیده
We investigate characterizations of the Galois connection sInv–Aut between sets of finitary relations on a base set A and their automorphisms. In particular, for A = ω1, we construct a set R of relations that is closed under all invariant operations on relations and under arbitrary intersections, but is not closed under sInv Aut.
منابع مشابه
ar X iv : m at h / 03 09 16 5 v 1 [ m at h . L O ] 9 S ep 2 00 3 Automorphisms and strongly invariant relations
We investigate characterizations of the Galois connection sInv–Aut between sets of finitary relations on a base set A and their automorphisms. In particular, for A = ω1, we construct a countable set R of relations that is closed under all invariant operations on relations and under arbitrary intersections, but is not closed under sInvAut. Our structure (A, R) has an ω-categorical first order th...
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