necessary and suftqcient conditions的用法和樣例：
例句
- Necessary and suffcient conditions for the existence of such strategies are established.
建立了關(guān)于這類(lèi)策略存在的充要條件。 - Finally, sufficient and necessary conditions for a fuzzy good congruence on an adequate semigroup to be idempotent-separated are proved.
最后，得到了適當半群上的模糊好同余為冪等可分的充要條件。
