Predicate Logic Notation: What does a “dot” mean?

Question

What does a dot (.) mean in predicates?

$\forall a \in A. \exists d \in D. H(a,d)$

Especially, how is the above different to

$ \exists d \in D. \forall a \in A. H(a,d)$

I've never seen this used in German lecture scripts.