On the distance between non-isomorphic groups
  A result of Ben-Or, Coppersmith, Luby and Rubinfeld on testing whether a map be two groups is close to a homomorphism implies a tight lower bound on the distance between the multiplication tables of two non-isomorphic groups. 
G\'abor Ivanyos, Fran\c{c}ois Le Gall, Yuichi Yoshida
math.GR cs.DM