Not On Permanent Ref: This commit is not an ancestor of any permanent ref.
This commit no longer exists in the repository. It may have been part of a branch which was deleted.This commit has been deleted in the repository: it is no longer reachable from any branch, tag, or ref.
Introduce LemmaList for better separation of concerns
LemmaList will be used to compare the list of lemmas edited by the
user to the original list of lemmas.