General sequencing question

[Basia W]

Hello,

I am sorry I can't quite remember which game this was from but I was wondering how to properly diagram this particular rule:

"F must be played immediately after R, unless G is played earlier than R"

I diagrammed it as a RF not block G>R

I wasn't sure if this was correct.

Thank you,

Basia

[Lucas Moreau]

Hello, Basia,

That is correct! Well done! Remember that any conditional statement can be rephrased into an "If...then..." sentence.

In this case, using the Unless Equation, we identify the necessary as the condition modified by "unless" (G is played earlier than R), and take the other condition (F must be played immediately after R), negate it (F is not played immediately after R), and that becomes the sufficient.

So we get "If F is not played immediately after R, then G is played earlier than R."

"F is not played immediately after R" is properly diagrammable as an RF not-block, so RF not-block G>R is correct.

Good job,
Lucas Moreau

[Basia W]

Hello,

Thank you for your reply! I'm glad it was correct it looked a little strange. Would the contrapositive of that statement be: if NOT G>R RF block?

Thanks again for being so thorough,

best,

Basia

[Lucas Moreau]

Hello, Basia,

A slightly better way to represent it would be:

R>G RF block

This is of course assuming that there are no ties possible. Which is fortunately true in most games! If there are ties possible, your NOT!G>R would be more effective.

Hope that helps,
Lucas Moreau

[Basia W]

Yes that was great!

Thank you,

best,

Basia