English

Vector spaces with an order unit

Operator Algebras 2009-06-10 v4

Abstract

We develop a theory of ordered *-vector spaces with an order unit. We prove fundamental results concerning positive linear functionals and states, and we show that the order (semi)norm on the space of self-adjoint elements admits multiple extensions to an order (semi)norm on the entire space. We single out three of these (semi)norms for further study and discuss their significance for operator algebras and operator systems. In addition, we introduce a functorial method for taking an ordered space with an order unit and forming an Archimedean ordered space. We then use this process to describe an appropriate notion of quotients in the category of Archimedean ordered spaces.

Keywords

Cite

@article{arxiv.0712.2613,
  title  = {Vector spaces with an order unit},
  author = {Vern Paulsen and Mark Tomforde},
  journal= {arXiv preprint arXiv:0712.2613},
  year   = {2009}
}

Comments

38 pages, uses XY-pic, Version 2 comments: minor typos corrected.; Version 3 Comments: minor typos corrected; Version 4 Comments: minor typos corrected, hypothesis of Archimedean added to Theorem 4.22, To appear in Indiana Univ. Math. J

R2 v1 2026-06-21T09:54:38.111Z