I think as long as the sage tree is not inside the app bundle then we are okay.
I just tried it by pulling out the sage directory from the Resources directory
and then pointing the preferences to that and it worked (there was a weird
warning about read only at first, but we can get that worked
The original paper of Jordan (1869) can be found at e.g.
https://www.degruyter.com/view/j/crll.1869.issue-70/crll.1869.70.185/crll.1869.70.185.xml
or https://eudml.org/doc/148084
But it is written in French in a German journal.
See the lecture notes of Erik Demaine
