Hello, I'm developing the geometric library for the summer of code 2007. In our design, we use descriptors similar to the graph library. But we are having problems with the descriptors especially when carrying out the erase methods for containers, where iterators are needed. In our case using iterators for list and set containers seems more natural than using descriptors. On the other hand, descriptors can be handled easily on vector, and they enable a stable way to access container elements under certain operations( such as resize). We are in the process of deciding whether to continue with the descriptors or iterators, or maybe something hybrid. I guess my main question is does using descriptors have advantages over iterators in the design or the runtime of the graph library? Also are there other specific reasons to use descriptors that you experienced? Any insight on this issue would be appreciated. Thanks, huseyin