Finite U-rank versus finite Morley rank in DCF_{0,m}

Determine whether every definable set of finite U-rank in the theory DCF_{0,m} has finite Morley rank.

Background

The paper studies the Kolchin-generic type of the inviscid Burgers equation in DCF_{0,2} and proves that this complete type has U-rank 1 but Morley rank ω. However, the corresponding definable solution set has both U-rank and Morley rank equal to ω.

The authors note that they have not found a definable set V in DCF_{0,2} with U(V)=1 and RM(V)=ω, and further establish for definable subsets V of their Burgers-equation solution set X that finite U-rank is equivalent to finite Morley rank. The question asks whether this equivalence holds for all definable sets in DCF_{0,m}.