- Mon Aug 03, 2020 10:20 am
That last rule uses the phrase "if, but only if", nowornever, and that creates a double arrow relationship. Each of those conditions is both sufficient and necessary for the other. In other words, either both of those things happen (P is first and Y is before V) or else neither of them happens (P is not first and V is before Y). There isn't really a contrapositive for that type of diagram, just an either/or situation. Either both things happen, or else neither of them happens. So there cannot be a situation where one thing (Y-V) occurs and the other (P1) does not.
Adam M. Tyson
PowerScore LSAT, GRE, ACT and SAT Instructor
Follow me on Twitter at https://twitter.com/LSATadam