My lecturer has abbreviated something and I can't find what it is. Here is how it has come up in my notes:
Lemma: In any integral domain, $p$ prime $\implies p$ irreducible.
Proof: Suppose $p$ is prime and $p = ab$. w.l.g $p \mid b$. So $cp = b$ for some $c \in R$...
What does that w.l.g bit mean? Does it make sense from there or shall I try and find another example?