7.2bOn page one of the tutorial we supposed that negative forms like
"No S are P"
could be symbolized in two standard ways. We chose one way:
~(%x)( Sx & Px )
But there is another standard way we have used:
(^x)( Sx > ~Px )
In the tutorial we had a particular sentence in mind:
(**) "No mammals are reptiles "
Now this could be symbolized in either of two ways:
(* in PL)
To show these two ways equivalent we'd do two derivations from one as premise to the other as conclusion. That's what you'll find in problems one and two. (Hint: if you can do one, you can do the other in just the opposite order.)