| 数学 |
necessary and sufficient (In logic, necessity and sufficiency refer to the implicational relationships between statements. The assertion that one statement is a necessary and sufficient condition of another means that the former statement is true if and only if the latter is true. Wiki. Thus, the most crucial task in the design of an intermittent mechanism is how to produce the dwell time necessary and sufficient to accommodate the completion of a prescribed series of operations. Klimzo Alexander Demidov) |
