24,830 research outputs found

    A treatment of collection data as constructor algebras

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    This paper gives algebraic definitions of various types of nested variable-length “collections” of elements, usable as data structures. First of all, however, the paper introduces constructor algebras through an integer sequences data type. It then begins with the fundamental CONS algebra of N-tuples and a variant with “negative" elements, complementing it and subsequent homogeneous algebras by heterogeneous ones. For such list algebras, the paper postulates axioms embodying the three “basic properties“ [Commutativity‚ Idempotence, Associativity], and uses these to define the remaining seven "basic collections" [strings‚ communes, acommunes, bags, abags, sets, heaps]. Proceeding to ”non-basic collections", it then introduces "adsorption" properties [”complementary" to absorption], which are characteristic for graphs, and postulates them as axioms in algebras of ordinary graphs and of directed recursive labelnode hypergraphs [DRLHs]. Finally, it defines the property of "Similpotence" [“weaker” than Idempotence] and postulates it for DRLHs with contact labelnodes, as applied in knowledge representation

    On the isomorphism problem of concept algebras

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    Weakly dicomplemented lattices are bounded lattices equipped with two unary operations to encode a negation on {\it concepts}. They have been introduced to capture the equational theory of concept algebras \cite{Wi00}. They generalize Boolean algebras. Concept algebras are concept lattices, thus complete lattices, with a weak negation and a weak opposition. A special case of the representation problem for weakly dicomplemented lattices, posed in \cite{Kw04}, is whether complete {\wdl}s are isomorphic to concept algebras. In this contribution we give a negative answer to this question (Theorem \ref{T:main}). We also provide a new proof of a well known result due to M.H. Stone \cite{St36}, saying that {\em each Boolean algebra is a field of sets} (Corollary \ref{C:Stone}). Before these, we prove that the boundedness condition on the initial definition of {\wdl}s (Definition \ref{D:wdl}) is superfluous (Theorem \ref{T:wcl}, see also \cite{Kw09}).Comment: 15 page

    Interval-valued algebras and fuzzy logics

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    In this chapter, we present a propositional calculus for several interval-valued fuzzy logics, i.e., logics having intervals as truth values. More precisely, the truth values are preferably subintervals of the unit interval. The idea behind it is that such an interval can model imprecise information. To compute the truth values of ‘p implies q’ and ‘p and q’, given the truth values of p and q, we use operations from residuated lattices. This truth-functional approach is similar to the methods developed for the well-studied fuzzy logics. Although the interpretation of the intervals as truth values expressing some kind of imprecision is a bit problematic, the purely mathematical study of the properties of interval-valued fuzzy logics and their algebraic semantics can be done without any problem. This study is the focus of this chapter

    Gradings, Braidings, Representations, Paraparticles: some open problems

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    A long-term research proposal on the algebraic structure, the representations and the possible applications of paraparticle algebras is structured in three modules: The first part stems from an attempt to classify the inequivalent gradings and braided group structures present in the various parastatistical algebraic models. The second part of the proposal aims at refining and utilizing a previously published methodology for the study of the Fock-like representations of the parabosonic algebra, in such a way that it can also be directly applied to the other parastatistics algebras. Finally, in the third part, a couple of Hamiltonians is proposed, and their sutability for modeling the radiation matter interaction via a parastatistical algebraic model is discussed.Comment: 25 pages, some typos correcte

    On the Strong Homotopy Lie-Rinehart Algebra of a Foliation

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    It is well known that a foliation F of a smooth manifold M gives rise to a rich cohomological theory, its characteristic (i.e., leafwise) cohomology. Characteristic cohomologies of F may be interpreted, to some extent, as functions on the space P of integral manifolds (of any dimension) of the characteristic distribution C of F. Similarly, characteristic cohomologies with local coefficients in the normal bundle TM/C of F may be interpreted as vector fields on P. In particular, they possess a (graded) Lie bracket and act on characteristic cohomology H. In this paper, I discuss how both the Lie bracket and the action on H come from a strong homotopy structure at the level of cochains. Finally, I show that such a strong homotopy structure is canonical up to isomorphisms.Comment: 41 pages, v2: almost completely rewritten, title changed; v3: presentation partly changed after numerous suggestions by Jim Stasheff, mathematical content unchanged; v4: minor revisions, references added. v5: (hopefully) final versio
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