Date
2016
Indexation documentaire
Algèbre
Subject
variable substitution; Boolean function; essential variable; arity gap; Finite function
Nom de la revue
Journal of Multiple-Valued Logic and Soft Computing
Volume
27
Numéro
2-3
Date de publication
2016
Pages article
193-207
Nom de l'éditeur
OCP Science
A paraître
oui
Auteur
Couceiro, Miguel
Lehtonen, Erkko
Type
Article accepté pour publication ou publié
Résumé en anglais
Let A be a finite set and B an arbitrary set with at least two elements. The arity gap of a function f:An→B is the minimum decrease in the number of essential variables when essential variables of f are identified. A non-trivial fact is that the arity gap of such B-valued functions on A is at most |A|. Even less trivial to verify is the fact that the arity gap of B-valued functions on A with more than |A| essential variables is at most 2. These facts ask for a classification of B-valued functions on A in terms of their arity gap. In this paper, we survey what is known about this problem. We present a general characterization of the arity gap of B-valued functions on A and provide explicit classifications of the arity gap of Boolean and pseudo-Boolean functions. Moreover, we reveal unsettled questions related to this topic, and discuss links and possible applications of some results to other subjects of research.