return only one dimension in multidimensional observation?

[doweichert]

Hej,

I just found your julia package and it looks great.

Anyway, I've got a short question. I've got a problem in a, say, two dimensional space and two actions that lead to observations only for one of the dimensions. To express it generator-like with (x, y)-tuples for actions a_1 and a_2:

((s'_x, s'_y), (o_x, ??), r) = G((s_x, s_y), a_1)
((s'_x, s'_y), (??, o_y), r) = G((s_x, s_y), a_2)

How can I express this best using the framework?

Thanks for your help.
Dorina