In mathematics, an O*-algebra is an algebra of possibly unbounded operators defined on a dense subspace of a Hilbert space. The original examples were described by and , who studied some examples of O*-algebras, called Borchers algebras, arising from the Wightman axioms of quantum field theory. and began the systematic study of algebras of unbounded operators.
All subspace regions of Hilbert space are dense.
( z1 dense :domain ( z2 region :mod ( z3 subspace ) :part-of ( z4 space :name ( z5 name :op "Hilbert" :op "Space" ) ) :mod ( z6 all ) ) )