On Regular Difference Terms

Set Constraints on Regular Terms

Set constraints are a useful formalism for verifying properties of programs. Usually, they are interpreted over the universe of finite terms. However, some logic languages allow infinite regular terms, so it seems natural to consider set constraints over this domain. In the paper we show that the satisfiability problem of set constraints over regular terms is undecidable. We also show that, if ...

Regular Difference Covers

Hybrid Constraints for Regular Terms

We define a family of constraints over the domain of regular terms. This family is built by extending equality with general constraints over root labels. We say that the resulting constraints are hybrid. Under the assumption that these constraints are stable with respect to a partial ordering we give an efficient constraint solver for hybrid constraints. We show in an example how the constraint...

Regular ordered semigroups and intra-regular ordered semigroups in terms of fuzzy subsets

Let $S$ be an ordered semigroup. A fuzzy subset of $S$ is anarbitrary mapping   from $S$ into $[0,1]$, where $[0,1]$ is theusual interval of real numbers. In this paper,  the concept of fuzzygeneralized bi-ideals of an ordered semigroup $S$ is introduced.Regular ordered semigroups are characterized by means of fuzzy leftideals, fuzzy right ideals and fuzzy (generalized) bi-ideals.Finally, two m...

A graphical difference between the inverse and regular semigroups

In this paper we investigate the Green‎ ‎graphs for the regular and inverse semigroups by considering the‎ ‎Green classes of them‎. ‎And by using the properties of these‎ ‎semigroups‎, ‎we prove that all of the five Green graphs for the‎ ‎inverse semigroups are isomorphic complete graphs‎, ‎while this‎ ‎doesn't hold for the regular semigroups‎. ‎In other words‎, ‎we prove‎ ‎that in a regular se...