Here is the predicate under consideration:

>Prime(x) ≡ x>1 ∧(∀y)(Divide(y,x) → (y=1 ∨ y=x)).

The goal is to write this as an English sentence. The *Divide* relation seems to suggest that y divides x, not that y is divisible by x. It might be represented in English as

>The natural number x is a prime number if x is greater than 1 and for all natural numbers y if y divides x then y = 1 or y = x.

As a check on primality, here is Wikipedia's definition of prime number:

>A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself.


Wikipedia contributors. (2019, June 7). Prime number. In Wikipedia, The Free Encyclopedia. Retrieved 04:32, June 16, 2019, from