English

Unbounded operators in Hilbert space, duality rules, characteristic projections, and their applications

Functional Analysis 2017-01-19 v2

Abstract

Our main theorem is in the generality of the axioms of Hilbert space, and the theory of unbounded operators. Consider two Hilbert spaces such that their intersection contains a fixed vector space D. It is of interest to make a precise linking between such two Hilbert spaces when it is assumed that D is dense in one of the two; but generally not in the other. No relative boundedness is assumed. Nonetheless, under natural assumptions (motivated by potential theory), we prove a theorem where a comparison between the two Hilbert spaces is made via a specific selfadjoint semibounded operator. Applications include physical Hamiltonians, both continuous and discrete (infinite network models), and operator theory of reflection positivity.

Keywords

Cite

@article{arxiv.1509.08024,
  title  = {Unbounded operators in Hilbert space, duality rules, characteristic projections, and their applications},
  author = {Palle Jorgensen and Erin Pearse and Feng Tian},
  journal= {arXiv preprint arXiv:1509.08024},
  year   = {2017}
}
R2 v1 2026-06-22T11:06:14.694Z