The "abc" conjecture (also known as the Oesterlé–Masser conjecture) is a conjecture in number theory, first proposed by and . It is stated in terms of three positive integers, "a", "b" and "c" (hence the name) that are relatively prime and satisfy "a" + "b" = "c". If "d" denotes the product of the distinct prime factors of "abc", the conjecture essentially states that "d" is usually not much smaller than "c". In other words: if "a" and "b" are composed from large powers of primes, then "c" is usually not divisible by large powers of primes. A number of famous conjectures and theorems in number theory would follow immediately from the "abc" conjecture or its versions. described the "abc" conjecture as "the most important unsolved problem in Diophantine analysis".