theorem
  m1 <> 0 & m2 <> 0 & m3 <> 0 & (not (m1 gcd m2) divides (a - b) or not
(m1 gcd m3) divides (a - c) or not (m2 gcd m3) divides (b - c)) implies not ex
  x st (x-a) mod m1 = 0 & (x-b) mod m2 = 0 & (x-c) mod m3 = 0 by Th41;
