Commit 2020-10-01 20:40 4ef680b1
View on Github →feat(group_theory): subgroups of real numbers (#4334) This fills the last hole in the "Topology of R" section of our undergrad curriculum: additive subgroups of real numbers are either dense or cyclic. Most of this PR is supporting material about ordered abelian groups. Co-Authored-By: Heather Macbeth 25316162+hrmacbeth@users.noreply.github.com