随伴作用素
In linear algebra and operator theory, given a bounded positive semidefinite operator (a non-negative operator) "T" on a complex Hilbert space, "B" is a square root of "T" if "T" = "B* B", where "B*" denotes the Hermitian adjoint of "B". According to the spectral theorem, the continuous functional calculus can be applied to obtain an operator "T"1/2 such that