Decomposability of extremal positive unital maps on $M_2$
| dc.creator | Majewski, Wladyslaw A. | |
| dc.creator | Marciniak, Marcin | |
| dc.date | 2005-09-30 | |
| dc.date | 2005-10-21 | |
| dc.date.accessioned | 2026-07-07T06:47:07Z | |
| dc.date.available | 2026-07-07T06:47:07Z | |
| dc.description | A map $ϕ:M_m(\bC)\to M_n(\bC)$ is decomposable if it is of the form $ϕ=ϕ_1+ϕ_2$ where $ϕ_1$ is a CP map while $ϕ_2$ is a co-CP map. It is known that if $m=n=2$ then every positive map is decomposable. Given an extremal unital positive map $ϕ:M_2(\bC)\to M_2(\bC)$ we construct concrete maps (not necessarily unital) $ϕ_1$ and $ϕ_2$ which give a decomposition of $ϕ$. We also show that in most cases this decomposition is unique. | |
| dc.description | 9 pages | |
| dc.identifier | https://arxiv.org/abs/math/0510005 | |
| dc.identifier | http://arxiv.org/abs/math/0510005 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/103552 | |
| dc.subject | Functional Analysis | |
| dc.subject | Operator Algebras | |
| dc.subject | 47B65, 47L07 | |
| dc.title | Decomposability of extremal positive unital maps on $M_2$ | |
| dc.type | text |