请问，inifinity minus在uvm中指的是什么呢？

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各位:
      本人最近在看《A Practical Guide Adoping the Universal Verificaiton Methodology》一书，在此书中的5.3.1一节中，提到infinity minus，本人英语不大好，理解不了，这一段讲的是神马，只能靠猜，不解之余只能上论坛来求助于诸位，不知有谁知否？原文如下：

Infinityminus—Randomnesshas proven as an efficient tool for uncovering unanticipated bugs. As youimplement your testbench it is a good practice to use all random values. Theinfinity minus flow means that a wide variety of values are randomized bydefault (infinity). Individual tests use constraints to trim the possible legalvalues to test-specific values. The opposite for infinity-minus is to startwith directed tests or a structured stimuli and finish with randomness at theend.

我蒙着一段的意思是说无穷的随机化，心中忐忑不敢肯定。还请各位高人不吝指点！