[按：下文是群邮件的内容，探讨"方法"和"应用"及其代价，略有修订。发明方法的人最好让诸使用者彼此竞争，因为每个使用者也会让诸方法彼此竞争。]

Why method inventors should not apply their inventions to "outside" problems by themselves?

---- Basically, new methods are perpendicular to each other.

---- Further, each mathematical method is perpendicular to every "outside" problem.

---- If one is going to apply one method to an "outside" problem, one needs to enter the outside domain.

---- Let the cost be A.

---- However, it appears wiser to develop a new method with a cost B instead of staying with the invented one.

---- The later choice is even right when A > B.

---- It is generally A >> B.

---- Also, "stand-alone" is better than "reliance" on a outside domain.

---- Further more, those applicaions may not be visible to your peers.

---- That is to say, the projection is zero on their mind.

---- One can depict the situation with a graph ——

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↑method

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Applications are expensive and only the strongest methods would be handed down...