I am sorry for the title, I have no idea how to call it. Having the truth table for this expression X and (Y or Z), I get 8 rows giving ALL possible combinations between them. When I take the "short-circuiting" (exluding the ones that have no meaning, e.g. TTF as F will never be evaluated because TT is enough) into consideration, only 4 will be left:
TT- TFT TFF F--
When I need a set where each variable gets at least once T or F, it will be exactly the same set. Is it by chance or is it always like that?