function gmin = condmin(Gf)
   [mt,ny,nu,nx] = minfo(Gf); gmin = []; 

%   [dum1,n,m,dum2]=minfo(Gf);
   zeroy = zeros(ny,ny);
   zerou = zeros(nu,nu);
   H = abv( sbs(zerou, vpinv(Gf)), sbs(Gf, zeroy));
%
%  H = |  [0]_{nuxnu}    G^{-1}    |
%      |      G       [O]_{nyxny}  |
%
%  
   blk0=[1 1]; blk1=blk0;
   for k=2:nu+ny
     blk1 = [blk1; blk0];   % All of size 1x1.
   end
%   blk2=blk1; blk=[blk1; blk2];
   blk = blk1;
   mu1=mu(H,blk,'Uc'); gmin1=sel(mu1,':',1);
   gmin=mmult(gmin1,gmin1);
end
