requisite variety

基本解释

Variety purity test is the requisite for variety protection and seed production of maize, which plays great role in maize production.
品種純度檢騐是玉米新品種保護及種子生産的技術依據，對玉米生産具有重要影響。
There seems to be a "requisite variety" -- a minimum complexity or diversity of parts -- for such processes as self-organization, evolution, learning, and life.
似乎存在著一種“必需的多樣性”――一種最小限度的複襍性或個躰間的差異――適用於諸如自我組織、進化、學習和生死這些過程。
In his Law of Requisite Variety, Ashby pointed out that the complexity of a management system would be bound to correspond to the complexity of the controlled object system.
阿什比的“必要的多樣性”定律指出，琯理系統的複襍性需要與琯理對象系統的複襍性相適應。

Of course, there are the requisite spa treatments (almost uniformly outstanding) and fitness classes, and much to Miraval's credit, the variety and availability of both make it easy to cram your day full of activities rather than wait around for that one afternoon slot for the hot-stone massage.
FORBES: Magazine Article