Logic Chains Bi-directionality

[arischacter]

Hi,

Just a question. I've been practicing using the logic chain for binary grouping games, but I seem to find myself confused, as to when an arrow should be bi-directional. In most circumstances, I understand that it's a single arrow when it says something like 'Jon and Tina cannot both be selected'.

Does the bidirectional apply on those constraints only when they both have to be selected into a group?

Cheers!

[bbirdwell]

The arrow goes both ways in mutually exclusive situations.

The reason it doesn't go both ways in the instance of "Jon and Tina cannot both be selected" is because that's not mutually exclusive. While the two cannot both be selected, they can both be "unselected."

When a constraint says "Jon and Tina cannot be in the same boat," then you have a mutually exclusive situation and use a double arrow.

Also, when there is the combination of "if and only if," you have a double arrow. Practically speaking, "only if" = "then," so in the case of "Jon is selected if, and only if, Tina is selected," you have two distinct statements: T --> J, and J --> T. Thus the double arrow.

Those are the only two specific situations that come to mind. Does that help?

[arischacter]

A ton! Thanks!