What do I need to get the blackboard style (double lines) characters for R (the set of real numbers) and Q (the set of rational numbers) in a ConTeXt document?
I've been using \mathbb{R} and \mathbb{Q}, but apparently that's MkIV only. However, {\blackboard R} and {\blackboard Q} seem to work both under MkII and MkIV (although the glyph shapes are different, but I assume that's font-related).