function [selected, maxsize] = subset_dominance(a)
tic; epsilon=.0000001; [n,n1]=size(a); 
for i = 1:n
  a(i,i) = 0;
end
d = zeros(n,n);
for i = 1:n-1
  for j = i+1:n
    if a(i,j) < a(j,i)
      d(i,j) = 0; d(j,i) = 1;
    elseif a(i,j) > a(j,i) 
      d(i,j) = 1; d(j,i) = 0;
    end
  end
end
maxsize = 0; q = zeros(1,n+1); s = zeros(1,n+1);
m = 1; q(m) = 1; s(1) = 1; trig1 = 0; trigend = 0;
while trigend == 0
  if trig1 == 0
    m = m + 1;  trig1 = 1;    % advance pointer
  end
  q(m) = q(m) + 1;
  if s(q(m)) == 1             % redundancy
    continue
  end
  if m == 1 && q(m) > n       % terminate
    trigend = 1;
    continue
  end
  if m > 1 && q(m) > n        % retract
    s(q(m)) = 0; q(m) = 0; m = m - 1; s(q(m)) = 0;
    continue
  end
  test_fail = 0; s(q(m))=1;
  if m > 1
     if a(q(m-1),q(m)) == a(q(m),q(m-1)) && q(m) < q(m-1)
        test_fail = 1; s(q(m)) = 0;
     end
  end
  if test_fail == 0
      for i = 1:m-1
          if d(q(i),q(m)) == 0
               test_fail = 1; s(q(m))=0;
               break
          end
      end
  end
  if test_fail == 0
    if m > maxsize
      maxsize = m; selected = q;
    end
    trig1 = 0; 
  end
end
toc