NONNEGATIVITY OF REDUCIBLE SIGN IDEMPOTENT MATRICES

  • Park, Se-Won (Department of Mathematics, SeoNam University) ;
  • Lee, Sang-Gu (Department of Mathematics, SungKyunKwan University) ;
  • Song, Seok-Zuk (Department of Mathematics, Cheju National University)
  • Published : 2000.05.01

Abstract

A matrix whose entries consist of the symbols +.- and 0 is called a sign pattern matrix . In 1994 , Eschenbach gave a graph theoretic characterization of irreducible sign idempotent pattern matrices. In this paper, we give a characterization of reducible sign idempotent matrices. We show that reducible sign idempotent matrices, whose digraph is contained in an irreducible sign idempotent matrix, has all nonnegative entries up to equivalences. this extend the previous result.

Keywords

References

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