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Indecomposable Positive Maps in Matrix Algebras

Published online by Cambridge University Press:  20 November 2018

Kôtarô Tanahashi  and
Jun Tomiyama
Kôtarô Tanahashi
Affiliation:
Department of Mathematics, Tohoku College of PharmacyKomatsushima, Sendai, 983, Japan
Jun Tomiyama
Affiliation:
Department of Mathematics, Tokyo Metropolitan UniversityFukasawa, Setagaya-Ku, Tokyo, 158, Japan
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Abstract

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We prove that Choi's map in M3 cannot be written as the sum of a 2-positive map and a 2-copositive map. We also provide other examples of positive maps in Mn which cannot be written as the sum of an n-positive map and a 2-copositive map.

Keywords

16A4215A30
Type
Research Article
Information
Canadian Mathematical Bulletin , Volume 31 , Issue 3 , 01 September 1988 , pp. 308 - 317
Copyright
Copyright © Canadian Mathematical Society 1988

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