Assume a partially ordered set (S,≤) and a relation R on S. We consider various sets of conditions in order to determine whether they ensure the existence of a least reflexive point, that is, a least x such that xRx. This is a generalization of the problem of determining the least fixed point of a function and the conditions under which it exists. To motivate the investigation we first present ...

In this paper we address the problem of solving recursive domain equations using uncountable limits of domains. These arise for instance, when dealing with the ω1-continuous function-space constructor and are used in the denotational semantics of programming languages which feature unbounded choice constructs. Surprisingly, the category of cpo’s and ω1-continuous embeddings is not ω0-cocomplete...

We give a complexity dichotomy for the Quantified Constraint Satisfaction Problem QCSP(H) when H is reflexive tournament. It well-known that tournaments can be split into sequence of strongly connected components H_1,...,H_n so there exists an edge from every vertex H_i to H_j if and only i<j. prove has both its initial final component (possibly equal) size 1, then in NL otherwise NP-hard.

It has recently been shown that a minimal reversible nonsymmetric ring order 256 answering question originally posed in paper on taxonomy of 2-primal rings. In different work, questions rings having to do with this were also answered. work it is abelian reflexive nonsemicommutative 256, related left open these previous works. here [Formula: see text] such ring. This consequence the main result ...