mathlib

767901ab - feat(algebra/ordered_ring): `a + 1 ≤ 2 * a` (#7995)

feat(algebra/ordered_ring): `a + 1 ≤ 2 * a` (#7995) Prove one lemma, useful for the Liouville PR #4301. The placement of the lemma will change, once the `ordered` refactor will get to `ordered_ring`.