【摘要】 讨论了二维Hilbert空间上线性算子正逼近的唯一性;对无限维Hilbert空间上存在唯一正逼近的线性算子进行了刻画;给出了一类线性算子不存在唯一正逼近的充分条件．更多还原

【Abstract】 The uniqueness of positive approximation for linear operators on two-dimensional Hilbert space is discussed in detail. In an infinite-dimensional case, a characterization is given when the unique positive approximation of a linear operator exists. Finally, a sufficient condition for some linear operators is presented if their unique positive approximations do not exist.更多还原