Title
Horn functions and submodular Boolean functions
Abstract
After providing a simple characterization of Horn functions (i.e., those Boolean functions that have a Horn DNF), we study in detail the special class of submodular functions. Every prime implicant of such a function involves at most one complemented and at most one uncomplemented variable, and based on this we give a one-to-one correspondence between submodular functions and partial preorders (reflexive and transitive binary relations), and in particular between the nondegenerate acyclic submodular functions and the partially ordered sets. There is a one-to-one correspondence between the roots of a submodular function and the ideals of the associated partial preorder. There is also a one-to-one correspondence between the prime implicants of the dual of the submodular function and the maximal antichains of the associated partial preorder. Based on these results, we give graph-theoretic characterizations for all minimum prime DNF representations of a submodular function. The problem of recognizing submodular functions in DNF representation is coNP-complete.
Year
DOI
Venue
1997
10.1016/S0304-3975(96)00202-2
Theor. Comput. Sci.
Keywords
DocType
Volume
horn function,submodular Boolean function
Journal
175
Issue
ISSN
Citations 
2
Theoretical Computer Science
9
PageRank 
References 
Authors
0.58
5
3
Name
Order
Citations
PageRank
Oya Ekin1695.34
Peter L. Hammer21996288.93
Uri N. Peled317322.91