Complex sentence: In number theory, Euclid's lemma (also called Euclid's first theorem) is a lemma that captures the most fundamental property of prime numbers, namely: if a prime divides the product of two numbers, it must divide at least one of those numbers.
Split into simpler sentences: In number theory, Euclid's lemma (also called Euclid's first theorem) is a lemma that captures one of the fundamental properties of prime numbers. It states that if a prime divides the product of two numbers, it must divide at least one of those numbers.