LG Bible Ch 5. Double Arrows

[lrock]

I'm using the logic games bible to refresh some of my conditional logic for in-out grouping games. I know that "X is selected if but only if Y is selected" means X and Y must always be selected (or not) together. However, I am confused about what this statement would mean: "X is selected if but only if Y is NOT selected". I think it means that one (and only one) of X and Y must be selected at all times, but would appreciate if someone could confirm!

Thanks!

[Nikki Siclunov]

Hi lrock,

That's exactly what it means You got it. "X is selected if but only if Y is NOT selected" can be diagrammed as:

X Y
Y X

Essentially, it requires that exactly one of X or Y is always selected. Another way to word the rule would be to say, "Either X or Y, but not both, is selected."

Hope this helps!

Thanks,