Suppose I asked: "Does every X have property Y?"
Then I want to rephrase the question for the reader, in order to make use of some special terminology...
In other words, "Can an X exist without property Y?"
But, of course, even though I am essentially asking the same thing, these two questions are not the same and have different answers (yes for the first question and no for the second)
How can I introduce the second version? What is the relationship called?