positive element
self-adjoint (or Hermitian) element A of a C*-algebra A is called positive if its spectrum σ (A) consists of non-negative real numbers
en-GB/ˈpɒzətɪv ˈɛlɪmənt/
en-US/ˈpɑzətɪv ˈɛləmənt/
self-adjoint (or Hermitian) element A of a C*-algebra A is called positive if its spectrum σ (A) consists of non-negative real numbers