function M3 = union_nfsa(M1,M2)
% M3 is the nfsa-union of M1 and M2
% see str2nfsa.m for basic nfsa definitions

nQ1 = length(M1.Q);
nQ2 = length(M2.Q);
nQ3 = nQ1 + nQ2 + 1;

q_link = nQ1 + 1;

M3 = M1;
M3.Q = 1:nQ3;
M3.q0 = q_link;

M3.F = union(M1.F,M2.F+q_link);
M3 = set_ndelta(M3,[q_link],['@'],{[M1.q0 M2.q0+q_link]});

for q = M2.Q
  for s = M2.ALF
    R = nfsa_delta(M2,q,s);
    M3 = set_ndelta(M3,[q+q_link],[s],{R+q_link});
  end
end

return