Hello. I was wondering if anyone could explain this to me:

I want to prove the validity of this argument:

If you are bigger then someone and smaller then someone else, you are between these two. x is bigger then y and smaller than z. Thus x is between y and z.

I want to do it with these predicates:

(F(x,y)∧¬F(x,z)) F= x is bigger than y

(M(x,y,z)) M= x is between y and z

I cant see how this could work in a predicate tree or is there any other method? Hope I made myself understood.