Another element, all, expresses the constraint that all child elements in the group may appear once or not at all, and they may appear in any order.

另外一个元素all，表示这样的约束：组中的所有子元素可以同时出现一次，或者都不出现，它们可以按任意的顺序出现。

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Nowadays, owing to many unresolved decision problems which have a lot of factors and complex condition of constraint, a multitude of contradictory problems appear.

当今尚待解决的许多复杂大系统的决策问题，涉及因素很多，约束条件也很复杂，出现了大量的不相容问题。

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Whereas, outside this regime a kind of response oscillation appear, with same period as the constraint.

而在振荡区域外体系则可出现对外控约束的纯粹响应性振荡，周期与外控约束电位振荡相同。

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