This is quite interesting. I looked up the paper you have mentioned and compared with the paper I received from University of Oslo. The title of the paper from University of Oslo is what I had posted earlier, which is different than the paper available at http://gdz.sub.uni-goettingen.de/. Also...
Thanks. As I mentioned I also have the original in German, however as I am labouring through the translation in English, I am not sure that I will be able to grasp all the nuances, hence the request.
It should be "Imaginaren". That is the closest I can type on the forum as it does not have the required fonts. I also looked up the message from the library which sent me the original paper in German, and they have also used the spelling in the title. It does represent the root of (minus) one...
I am looking for the translation in English of the "Representation der Imaginiren der Plangeometrie" by Sophus Lie. If anyone knows where can I find it I will very much appreciate it. Thank you.