Topological fields with a generic derivation

We study a class of tame L-theories T topological fields and their Lδ-extension Tδ⁎ by generic derivation δ. The under consideration include henselian valued characteristic 0 real closed fields. show that the associated expansion has L-open core (i.e., every Lδ-definable open set is L-definable) derive both cell decomposition theorem transfer result elimination imaginaries. Other properties such as relative field sort quantifiers, NIP distality also to Tδ⁎. As an application, we consequences for corresponding theories dense pairs. In particular, theory pairs (resp. p-adically fields) admits distal expansion. This gives partial answer question P. Simon.