Definitions | x:A. B(x), Prop, P  Q, x(s1,s2), mapl(f;l), map(f;as), Y, True, Top,  x,y. t(x;y), t T, P & Q, P Q, {T}, l[i], {i..j }, ||as||, i j < k, hd(l), nth_tl(n;as), if b t else f fi, i j,  b, i< j, true , false , x L. P(x), x:A. B(x), A & B, P  Q, P  Q, (x l) |