Commit 2020-08-17 16:59 472251b0

feat(algebra): define linear recurrences and prove basic lemmas about them (#3829) We define "linear recurrences", i.e assertions of the form ∀ n : ℕ, u (n + d) = a 0 * u n + a 1 * u (n+1) + ... + a (d-1) * u (n+d-1), and we introduce basic related lemmas and definitions (solution space, auxiliary polynomial). Currently, the most advanced theorem is : q ^ n is a solution iff q is a root of the auxiliary polynomial.