24,830 research outputs found
A treatment of collection data as constructor algebras
This paper gives algebraic definitions of various types of nested variable-length âcollectionsâ 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 ânegative" elements, complementing it and subsequent homogeneous algebras by heterogeneous ones. For such list algebras, the paper postulates axioms embodying the three âbasic propertiesâ [Commutativityâ Idempotence, Associativity], and uses these to define the remaining seven "basic collections" [stringsâ communes, acommunes, bags, abags, sets, heaps]. Proceeding to ânon-basic collections", it then introduces "adsorption" properties [âcomplementary" 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" [âweakerâ than Idempotence] and postulates it for DRLHs with contact labelnodes, as applied in knowledge representation
On the isomorphism problem of concept algebras
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
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 âp implies qâ and âp and qâ, 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
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
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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