In his Enquiry concerning human understanding, Hume provides the following definition:
All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, Relations of Ideas, and Matters of Fact. Of the first kind are the sciences of Geometry, Algebra, and Arithmetic; and in short, every affirmation which is either intuitively or demonstratively certain.
He does not go any further in the explanation of this concept(at least as far as I've read), and I'm not sure I've understood well what a "relation of ideas" is. Is it the same as the analytic a priori judgment?