symbolic n;
R := {[i,j]: i >= 1 && i <= 101 &&
             j >= i && j <=401 && exists (alpha : j = 2 alpha)};
codegen R;
S := {[i,j]: i >= 1 && i <= 101 && exists (alpha : i = 2 alpha) &&
             j >= i && j <=401 && exists (alpha : j = 2 alpha)};
codegen S;
T := {[i,j]: i >= 1 && i <= 101 && exists (alpha : i = 2 alpha) &&
             j >= i && j <=401 && exists (alpha : 2j = 4 alpha)};
codegen T;