This exercise contain arguments from a single set of premises. In each case decide whether or not the argument is valid. If it is, give an informal proof. If it isn't, use Tarski's World to construct a counter example. Ax Ay [LeftOf(x; y) ->Larger(x; y)] Ax [Cube(x) -> Small(x)] Ax [Tet(x) ->Large(x)] Ax Ay [(Small(x) ^ Small(y)) -> ~Larger(x; y)] Az Aw [(Tet(z) ^ Cube(w)) -> LeftOf(z;w)]