4-dimensional F4 polytopes and their dual polytopes have been
constructed as the orbits of the Coxeter-Weyl group W(F4) where the group
elements and the vertices of the polytopes are represented by quaternions.
Branchings of an arbitrary \textbf{W(F4)} orbit under the Coxeter groups
W(B4 and W(B3)×W(A1) have been presented. The role of
group theoretical technique and the use of quaternions have been emphasizedComment: 26 pages, 10 figure