Example: Goldbach conjectured in 1742 that every even number bigger than 2 could be written as the sum of two primes. Until today this conjecture remains unproved. Consider the term “The first number that violates Goldbach’s conjecture”. It does not give us all information about the number, since the number might not exist. The prefix “the first” ensures the description, if it exists, is unique, and it gives us an algorithm to find the number. It is a partial uniquely identifying description. Th