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Paper IPM / M / 56  


Abstract:  
In a previous paper we introduced a generalized model for
translation invariant (TI) operators. In this model we considered
the space, Φ, of all maps from an abelian group G to
Ω∪{−∞}, called LGfuzzy sets, where Ω is a
complete latticeordered group; and we defined TI operators on
this space. Also, in that paper, we proved strong reconstruction
theorem to show the consistency of this model. This theorem states
that for an orderpreserving TI operator Y one can explicitly
compute Y(A), for any A, from a specific subset of Φ
called the base of Y. In this paper duality is considered in the same general framework, and in this regard, continuous TI operators are studied. This kind of operators are characterized in terms of critical points of their kernels. A critical point is defined to be a point at which there exists a net which converges to −∞, when −∞ is the value of a nontrivial limitfunction of the kernel at that point. A critical point is called to be of first type if for every such net there exists some other point at which this net converges to +∞, and it is called to be of second type otherwise. As the main result of this paper we prove that a welldefined isotone TI operator is continuous if and only if it has no critical point of second type. Moreover, in this case a TI operator has a continuous extension by duality. Download TeX format 

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