Do you know of any PhD programs that are highly flexible? I'm interested in either math or computer science programs, as I have done research in both areas and feel confident to apply to both.
With high flexibility I mean that there should be freedom for the PhD student to choose:
who they work with (so that I can get to work with different researchers - I have already done a number of internships and have built a small network of collaborators, and I want to keep these collaborations alive, even if they can't be all brought the umbrella of one single PhD topic)
from where they work (this is tied to 1): it is very difficult at times to work through skype and having different collaborators entails the need to travel and do work at different places)
I have met only one single PhD student who was able to do that - he spent the first year at his home university in Sidney, then he was 6 months in another country, then 6 month again in Sydney and then again away for an internship. I was quite impressed by the network he build and his research output.
EDIT I'm from Europe and I'm in particular interested in PhD programs in (continental) Europe. Though I might consider the US, if it is known in advance that there's a large amount of flexibility. The domains that I'm interested is analysis/data science/topology, so probably in any of these I should be able to find a suitable topic and will make the choice mainly on how much flexibility I'll be offered.