in this paper, we introduce the concept of semihyperring $(r,+,cdot)$ together with a suitable partial order $le$. moreover, we introduce and study hyperideals in ordered semihyperrings. simple ordered semihyperrings are defined and its characterizations are obtained. finally, we study some properties of quasi-simple and $b$-simple ordered semihyperrings.

In access control frameworks with the possibility of delegating permissions and administrative rights, delegation chains can form. There are different ways to treat these delegation chains when revoking rights, which give rise to different revocation schemes. Hagström et al. [11] proposed a framework for classifying revocation schemes, in which the different revocation schemes are defined graph...

Starting from Katsuno and Mendelzon postulates, a new set of postulates which is minimal and complete has been deened, these postulates characterize an update operator. The update operator class which is obtained is larger than Katsuno and Mendelzon's one, since it includes updating operators which are not inert, and which allow for the existence of unreachable states. The main property is that...

in this note first we define the notions of fuzzy positive implicativehyper bck-ideals of types 1,2,3 and 4. then we prove some theorems whichcharacterize the above notions according to the level subsets. also we obtainthe relationships among these notions, fuzzy (strong, weak, reflexive) hyperbck-ideals and fuzzy positive implicative hyper bck-ideals of types 5,6,7and 8. then, we define the no...

Using only the reciprocity postulate, it is demonstrated that the spatial separation of two objects, at rest in some inertial frame, is invariant. This result holds in both Galilean and special relativity. A corollary is that there are no 'length contraction' or associated 'relativity of simultaneity' effects in the latter theory. A thought experiment employing four unsynchronised clocks and a ...