commutant

English edit

commutant (plural commutants)

(algebra, logic) The subset of all elements of a semigroup that commute with the elements of a given subset
- 2008 September 27, John Earman, “Superselection Rules for Philosophers”, in Erkenntnis, volume 69, number 3, →DOI:
  The basic mathematical entity to be used here in elucidating the different senses of superselection rules is a von Neumann algebra ${\mathfrak {M}},$ a concrete C * -algebra 6 of bounded linear operators acting on a Hilbert space 7 ${\mathcal {H}}$ that is closed in the weak topology 8 or, equivalently, 9 that has the property that $({\mathfrak {M}}^{\prime })^{\prime }:={\mathfrak {M}}^{\prime \prime }={\mathfrak {M}},$ where “′” denotes the commutant.