| 释义 |
duality In many areas of mathematics, for a given problem it is possible to describe a dual problem. Solving the dual problem, rather than the original problem, can sometimes be easier, or recognizing the implications of the dual problem can be of benefit. This is particularly true of projective geometry. In a projective plane (see projective space), lines are dual to points, and concurrency is dual to collinearity. Thus ‘two points lie on a unique line' is dual to ‘two lines meet in a unique point'; proving one result immediately implies the other.
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