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How do you translate this rule...?
K is evaluated either at some time after M or at some time before T, but not both.
Thanks for the help!
0
How do you translate this rule...?
K is evaluated either at some time after M or at some time before T, but not both.
Thanks for the help!
10 comments
Which PT is this from? I don't recall seeing any worded exactly like this. I have seen some that sound a little similar but end up translating to M for example being in between the other two.
I think using the biconditionals would be the best way. Thanks guys!
Yeah, that didn't work! Ha! I tried!
I got the same as above but wanted to see if I could get the diagram to display correctly here.
T T
\ /
K or K
/ \
M M
K is evaluated either at some time after M or at some time before T, but not both.
While the approaches above are definitely correct from a logic standpoint, I find that in practice it's been most useful to note this rule as:
M and T before K OR K before M and T (These would be represented with two minitrees on paper, but I have no idea how to do this with text).
It's a fairly common rule, and it's meant to (weirdly) say that M and T are always on the same side of K in the game diagram: either both before, or both after.
These sorts of rules are usually a good indicator for splitting the board. For a lot of the games I found that there are two such rules, and you end up with 4 "trees". A quick glance at the appropriate tree tends to solve the vast majority of questions without any further work.
This is the deeper meaning of this rule. Really what it means is that K cannot split M and T. M and T must both either proceed or follow K.
Looked back to lesson on biconditionals, and this would be considered one, not a rule just akin to one.
If you were to diagram this as a rule in an LG, I wonder if using a double arrow (similar to one used for biconditionals) would be best for this. Since the rule is "or, but not both," neither /A - B, nor A - /B will work here, since both could be in or both out, respectively - or, in this case, before one and after another and vice versa.
Using a double arrow, you could diagram the rule you cited like this:
K - T (----) K - M
T - K (----) M - K
In this way, you avoid the trap of satisfying the necessary condition in a single arrow rule, thus allowing the rule to "fall away." Doing this would be ignoring the fact that both sides act as sufficient and necessary conditions.
This, in English, translates back to the actual rule: If before T, K must be before M, and vice versa. Or, If after M, K must be after T, and vice versa.
@ioana200 are you sure that's right? Here's what I would get:
"Either MK or KT, but not both" means "exactly one," which would be:
MK ↔ /KT
(/MK ↔ KT)
K is either after both M and T
or
K is before both M and T