so we know that there's going to be just one association for each object of c1, and if there's only going to be one association actually we could take these attributes and we could put those attributes as part of c1 instead of having a separate association class, so for example if this class happened to be the student class, and this was the college class, and we insisted that each student apply to exactly one college then the attributes we had down here, the date and decision, could be moved into the student class, because we know they're only applying to one college, so that would be the date and the decision for the one college they're applying to.