In this paper we study the problem of deciding boundedness of (recursive) regular path queries over views in data integration systems, that is, whether a query can be re-expressed without recursion. This problem becomes challenging when the views contain recursion, thereby potentially making recursion in the query uncessary. We define and solve two related problems of boundedness of regular pat...

For A(t) and f (t, x, y) T -periodic in t , we consider the following evolution equation with infinite delay in a general Banach space X: u′(t)+A(t)u(t)= f (t, u(t), ut ), t > 0, u(s)= φ(s), s 0, (0.1) where the resolvent of the unbounded operator A(t) is compact, and ut (s) = u(t + s), s 0. By utilizing a recent asymptotic fixed point theorem of Hale and Lunel (1993) for condensing operators t...

When A is a Lipschitz function, the L boundedness of %A is well understood and several proofs of it have been produced (cf. [C, CJS, CMM, DJ, M]). If A is a C -smooth function, then the local L boundedness of ̂ A is also well understood (cf. [FJR]). However, if A is a smooth, not necessarily Lipschitz function, the question of global L boundedness of ί?A has not been settled. In [KS], we observe...

In this paper we introduce a notion of multilinear localization operators. By reinterpreting these operators as multilinear Kohn-Nirenberg pseudodifferential operators, we prove that these multilinear localization operators are bounded on products of modulation spaces. In particular, by assuming that the symbols of the localization operators belong to the largest modulation space, i.e., M , we ...

In the present paper, we shall give necessary and sufficient conditions for the strong and weak boundedness of the Riesz potential operator [Formula: see text] on Orlicz spaces. Cianchi (J. Lond. Math. Soc. 60(1):247-286, 2011) found necessary and sufficient conditions on general Young functions Φ and Ψ ensuring that this operator is of weak or strong type from [Formula: see text] into [Formula...

We provide complexity characterizations of model checking multi-pushdown systems. We consider three standard notions for boundedness: context boundedness, phase boundedness and stack ordering. The logical formalism is a linear-time temporal logic extending well-known logic CaRet but dedicated to multi-pushdown systems in which abstract operators are parameterized by stacks. We show that the pro...

We define the (w∗-) boundedness property and the (w∗-) surjectivity property for sets in normed spaces. We show that these properties are pairwise equivalent in complete normed spaces by characterizing them in terms of a category-like property called (w∗-) thickness. We give examples of interesting sets having or not having these properties. In particular, we prove that the tensor product of tw...

in this paper, we study the existence, asymptotic behavior of the positive solutions of a fuzzy nonlinear difference equation$$ x_{n+1}=frac{ax_n+x_{n-1}}{b+x_{n-1}}, n=0,1,cdots,$$ where $(x_n)$ is a sequence of positive fuzzy number, $a, b$ are positive fuzzy numbers and the initial conditions $x_{-1}, x_0$ are positive fuzzy numbers.