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No abstract uploaded!

The paper mainly discusses, based on the properties and related knowledge of continuous functions, the conditions that the graphs of separated binary polynomials are closed curves by the method of separation of variables. It also studies the properties of closed curves in the ways of analytic geometry, and draws a sucient and necessary condition to determine whether the graph of a separated binary polynomial is closed.

No abstract uploaded!

In this note, we will discuss how to relate an operator ideal on Banach spaces to the sequential structures it defines. Concrete examples of ideals of compact, weakly compact, completely continuous, Banach-Saks and weakly Banach-Saks operators will be demonstrated.