The Abiteboul and Beeri algebra for complex objects can express a query whose meaning is transitive closure, but the algorithm naturally associated to this query needs exponential space. We show that any other query in the algebra which expresses transitive closure needs exponential space, under a \call by value" evaluation strategy. This proves that in general the powerset is an intractable op...

We study the problem of listing all closed sets of a closure operator σ that is a partial function on the power set of some finite ground set E, i.e., σ : F → F with F ⊆ P(E). A very simple divide-and-conquer algorithm is analyzed that correctly solves this problem if and only if the domain of the closure operator is a strongly accessible set system. Strong accessibility is a strict relaxation ...

Projection-based reduced order models (PROMs) have shown promise in representing the behavior of multiscale systems using a small set generalized (or latent) variables. Despite their success, PROMs can be susceptible to inaccuracies, even instabilities, due improper accounting interaction between resolved and unresolved scales system (known as closure problem). In current work, we interpret mul...

The results of this paper spring from the elementary fact that an algebraic function satisfies a linear differential equation. Let k0 be a number field and k0 be its algebraic closure. Let P ∈ k0(x)[y] be a squarefree polynomial of degree n in y. The derivation δ = d dx extends uniquely to the algebraic closure k0(x) of k0(x). We define the minimal operator associated with P to be the monic dif...

In this paper, we introduce a new subclasses of univalent functions defined in the open unit disc involving DziokSrivastava Operator . The results on modified Hadamard product ,Holder inequalities and closure properties under integral transforms are discussed.

In this paper we have characterized the epimorphisms in the full subcategory of Hausdorff fuzzy topological spaces (introduced by Srivastava et al.[10]) of the category FTS of fuzzy topological spaces and fuzzy continuous functions using the Salbanytype closure operator.

In this paper first order theories for nonmonotone inductive definitions are introduced, and a proof-theoretic analysis for such theories based on combined operator forms à la Richter with recursively inaccessible and Mahlo closure ordinals is given.

I describe a way of blurring an exponential field in a way which preserves the natural closure operator. The results of blurring the complex exponential field and of blurring Zilber’s exponential field are isomorphic.

This paper deals with closure properties of models of fuzzy attribute implications. Fuzzy attribute implications are particular IF-THEN rules which can be interpreted in data tables with fuzzy attributes and/or ranked data tables over domains with similarity relations. We show that models of any set of fuzzy attribute implications form a fuzzy closure system with hedge. Conversely, we show that...