Setup and Rule Diagrams

[srcline@noctrl.edu]

Hello

So I'm not quite understanding how the first two rules are sequential. Too me this sounded like conditional logic, b/c of the until that is thrown in there. I understood the first rule for example :

1. R cannot evaluate any intro. book until Juarez has evaluated that textbook

(+) If J has not evaluated an intro book R can evaluate an intro book

2. J cant evaluate any adv, textbook R has evaluated that textbook

(+)If R has not evaluated an adv. textbook J can evaluate adv. textbook

I saw the explanations that Dave and Nikki had posted and they did make sense, but I do not understand how these two rules are sequential in nature. I read Until as meaning that either J or R must have evaluated a book.
Much help is appreciated with this game
Sarah

[Clay Cooper]

Hi Sarah,

Thanks for your question.

The rules can be thought of as conditional OR sequential. Dave and Nikki (and I) favor thinking of them as sequential because it is more useful for this game.

Your rule diagrams are incorrect, and that, I think, is what has thrown you off. You are correct to use the unless formula. Remember though, that when we are using it, we take the condition modified by the unless (or in this case, 'until') and make it the necessary condition. Then, we negate the other term, and make it the sufficient condition. I think you just forgot to negate the second term when you made it the sufficient condition.

So, in conditional form, the rules should look like this:

1. R evaluate intro book --> Juarez already has evaluated it

and

2. J evaluate advanced --> R already has evaluated it.

As you can see, the usefulness of these two rules is that they will give us information about where particular books fall in each reviewer's sequence; that is why Dave and Nikki think of them as sequencing rules. And, since they are more efficiently used as sequencing rules, it makes sense to diagram them that way.

I hope that clarifies it somewhat.

[lathlee]

I think this game deserves a spot in Honorable mentions of Hardest LG ever. NO?

[ava17]

Hi! I have a general question about this game. There's a lot of variables that are affected by the same rules and therefore interchangeable (F is basically the same as G etc). In this situation, could I cut down on time I need to make hypos by mentally substituting variables? For eg, If I had made a valid hypo where F was in week 6, and a question asked whether H could be in week 6, would it be a smart idea to mentally substitute H for F in that hypo without making a new local diagram? Are there any potential downsides to this approach? Thanks!

[Robert Carroll]

Ava,

That strategy is actually vital for solving games efficiently. Know which variables have the same restrictions on each other and you'll be able to recognize when a given hypothetical can easily be converted into a number of similar hypotheticals when useful. Make sure, of course, that those conversions are permitted. If, say, the local condition of a question says "If F is later than H" then I can't exactly put F last! If you make sure to track ALL the conditions (Global and Local), though, you'll avoid this problem.

I actually think that, for the purposes of retaining your work so you can check it later or exploit it for future questions, you might want to write a brief note below the first local diagram like "Switch F and H and it also answers the next question" just so that your work isn't PURELY mental. This allows you to check why you thought that was true later if you need to; you don't have to just rely on your memory.

Robert Carroll