I like to think of the necessary element as something that logically or (necessarily follows) the condition of sufficiency. I anticipate that the difficulty lies in distinguishing ambiguous sets and correctly categorizing the relationship. very similar to if then statements.

for ''most'' or conditional relations, if A it follows that B. So negating that means if A is true, B does not follow. But then why Isnt it A -> /B. If A follows then not the opposite of B follows is what it is saying. Does this mean Negating with a conjunction means that A and B can never be true? e.g A &