Sequencing Rules of Logic Games

[brittany259]

Hello All, I am so happy I have decided to study the PowerScore Bibles, but I am a little confused on the introduction of the logic games.

Question 1:
On page 69 of the Logic Games bible problem #3, while I understand how we come to the rule diagram, I don't understand how we get all of the Not Laws. Could you please explain it to me? I get confused after finding all of the "C" Not Laws.

Question 2:
It seems that when Branched Sequencing is used, like on page 50, that we can find the Not Laws by negating the variable that has to come first the amount of spaces as the number of variables that has to come afterwards.
Clarity:
In the Triple Branched Sequence, "A" has to come before "B,C, & D". Well, "A" is noted as a Not Law in the last 3 spaces which is that same number of variables that has to come after it; and "B,C,D" are all negated in space one. So, is assumption accurate?

[Jon Denning]

Hey brittany,

Thanks for the message and welcome to the Forum! I'm really happy to hear you're enjoying the Logical Games Bible, and also glad to see that you're taking the time to ask questions early on when things aren't totally clear. That's how you build a strong foundation, so that when you reach later chapters and concepts you're well-prepared to tackle them!

For problem #3, those Not Laws are the result of impossible placements based on the large block of D E _ _ C. So you can look at it letter by letter (C, D, E) and determine where placements of each would cause problems.

The way I usually do that is by asking of a variable, "how many items must be before it, and how many must be after it?" Not Laws occur when the variable is placed somewhere that doesn't allow enough room for the other variables to fit. Let's try it here:

C: C has at least four things ahead of it (the D, E, and two spaces), meaning it cannot go anywhere in the first four spaces. If it did there wouldn't be room ahead of it for all four of the other variables in the block! That's why you get Not Laws under 1-4 for C.

D: D is the exact opposite, in that it has to have at least four things after it (the E, two spaces, and the C), meaning it cannot go anywhere in the final four spaces. Putting D too far towards the end of the base wouldn't allow room for the block's other variables. So you get Not Laws under the last four spots—3, 4, 5, 6—for D.

E: E has variables on both sides of it, so we'll need to leave room open both ahead, and after, E. Ahead of E is at least one variable, D. So E cannot go first (if it did D couldn't be ahead of it), and there's a Not Law under 1 for E. E also has at least three variables after it, so we get Not Laws under the final three spots—4, 5, 6—for E.

And that's it! The key is to consider each variable individually, and see the minimums of what appear before and after it. Those minimums are the spaces that need to be left open, so the variable in question can't fill them.

For your second question you're exactly right, but it's not just for branched chains! Any sequence's Not Laws can be determined by looking at each variable and simply counting what's ahead of it, and what's after it, as described in the preceding paragraph.

So keep at it and feel encouraged to really take your time with this early content; it gets much easier with time but it's hard to progress to the more difficult stuff if these initial ideas are unclear.

I hope that helps!

Jon