October 20, 2017 at 12:48 pm #3326DavidParticipant
Question 2 in set 4 Page 213 of Mike’s book. The question starts out with a coach will select some of the players trying out for the varsity eam. The 4th conditional States “if Nick is selected for junior varsity odis will be too. In my mind that reads N—>O, with contrapositive notO—>notN
Mike has it written as O—>N, notN—>notO.
This one condition is throwing off the entire game for me. What am I missing? Doesn’t if Nick introduce the sufficient condition and odis introduces the necessary?
October 20, 2017 at 3:22 pm #3328Mike KimKeymaster
Hey David —
I think your understanding of how the rule works is correct, and I think the confusion is caused by the general way in which we’ve set up the game —
For this game, there are two possible outcomes for the participants — varsity or junior varsity — for the notations, my suggestion is to notate this as a selection, or in/out, game, so that getting selected for the varsity is “in” and getting selected for junior varsity is “out” — you can also think of not being on varsity = being on junior varsity, and not being on junior varsity = being on varsity.
So, per that way of setting things up, N on varsity would be notated with a simple N, and N on junior varsity would be notated with an N crossout (meaning he is not on varsity) —
So, that rule reads “If N is selected for JV, O will be too.” —
You could have thought of this as Njv -> O jv, and crossout of O jv -> crossout of Njv, and that would have been correct as well, but –
Again, per the way we’ve set up the game (with N crossout meaning N jv) along with the inference that not being on jv means being on varsity, we end up with the way I notated it in the book:
/N -> /O, and O -> N.
Hope that makes sense — I realize that this situation is pretty much the textbook example of a complicated double-negative, and it’s tough to explain in words, so if I haven’t done a good enough job / if you have any follow-up, just let me know —
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