Hi,
Unfortunately we have not yet had time to define an interface for factored POMDPs yet, although the current POMDPs.jl interface should be quite capable of accommodating one. Of course, you can solve any POMDP with POMDPs.jl, but there is currently no way for the solvers to take advantage of any factorization. What formalism of factorization are you trying to use (can you link to a paper or something)? If you would like to take a stab at designing a factored interface and modifying solvers to take advantage of it, I'd be happy to advise you!
- Zach