Conditional LG rule with subset features

Skywalker

Dear All,

I am getting confused on what the contrapositive is for conditional rules in LG that have a subset feature.

For example, if you a grouping game, and there are 3 groups (A, B, C) and the rule states, if P is not in A, then H is not in A. What is the contrapositive of that?

BinghamtonDave

The rule is saying that the absence of P in group a implies the absence of H in group a. Contrapositive of this is H(subscript a)------>P(subscript a). What this means in plain English (and the way I tell myself when I am reading) is that if H is in group a then there better be a P in group a. P in group a is the necessary condition for H in group a. So if you have a scenario in which H ends up in group a and P ends up in group c, you have violated this condition. If you have a scenario where P is in group a, H can either go into a or go somewhere else (assuming no other rules restrict H's whereabouts.)


Hope this helps.

Skywalker

Thank you!!!!

BinghamtonDave

Because I like your username so much, I drew this out for you a bit more visually.

Fixing link to picture*

BinghamtonDave

inactive

Fixed your link, David! You can't link images directly from your computer, they need to be uploaded to an image hosting site.