A twistor construction of the hierarchy associated with the hyper-KK ahler equations on a metric (the anti-self-dual Einstein vacuum equations, ASDVE, in four dimensions) is given. The recursion operator R is constructed and used to build an innnite-dimensional symmetry algebra and in particular higher ows for the hyper-KK ahler equations. It is shown that R acts on the twistor data by multipli...

In this paper, we interrelate the intuitionistic fuzzification of the concept of BCI-(positive implicative, implicative, commutative) ideals in BCI-algebras and investigate some of their properties.

Implicative verbs (e.g. manage) entail their complement clauses, while non-implicative verbs (e.g. want) do not. For example, while managing to solve the problem entails solving the problem, no such inference follows from wanting to solve the problem. Differentiating between implicative and non-implicative verbs is therefore an essential component of natural language understanding, relevant to ...

Copyright q 2010 Young Bae Jun et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Based on the theory of falling shadows and fuzzy sets, the notion of a falling fuzzy implicative ideal of a BCK-algebra is introduced. Relations...

in this paper we define the notions of ultra and involution ideals in bck-algebras. then we get the relation among them and other ideals as (positive) implicative, associative, commutative and prime ideals. specially, we show that in a bounded implicative bck-algebra, any involution ideal is a positive implicative ideal and in a bounded positive implicative lower bck-semilattice, the notions of...

The notion of positive implicative vague ideals in BCKalgebras is introduced. A relation between a vague ideal and a positive implicative vague ideal is discussed. Characterizations of a positive implicative vague ideal are considered. 2010 AMS Classification: 06F35, 03G25, 03E72

Molodtsov's soft set theory provides a general mathematical framework for dealing with uncertainty. The concepts of (M, N)-SI implicative (Boolean) filters of BL-algebras are introduced. Some good examples are explored. The relationships between (M, N)-SI filters and (M, N)-SI implicative filters are discussed. Some properties of (M, N)-SI implicative (Boolean) filters are investigated. In part...

The notions of coupled N -subalgebra, coupled (positive implicative) N -ideals of d-algebras are introduced, and related properties are investigated. Characterizations of a coupled N -subalgebra and a coupled (positive implicative) N -ideals of d-algebras are given. Relations among a coupled N -subalgebra, a coupled N -ideal and a coupled positive implicative N -ideal of d-algebras are discussed.

In this paper, the authors study the notion of n-fold implicative and fuzzy n-fold implicative filters, which correspond to various sets of provable formulaes, in BL-algebras. Several characterizations of fuzzy n-fold implicative filters are given and the authors analyse some relationships with various n-fold and fuzzy n-fold filters in BL-algebras, while constructing some algorithms for studyi...