This paper can be served as a natural and wide popularization of the theory of non-standard real number. When all the (X_i, +, ·, ≤, )(i∈I) are topologically ordered fields, three structures, algebraic structure+a...
In this paper,we study mainly properties of a class approx mate ope rator in Hilbert space, form as S=T+Q where T is a power class (N) operator and Q is a quasinilpotent opera tot with TQ=QT. We discuss relation of ke...