theorem Th75:
  for n being non zero Nat
  holds the multF of INT.Group n = addint n
proof
  let n be non zero Nat;
  thus the multF of INT.Group n =
    the multF of (multMagma(# (Segm n),(addint n) #)) by GR_CY_1:def 5
  .= addint n;
end;
