Magnitude conjecture

MagnitudeConjecture.Combinatorics.SurplusCounts

Surplus in terms of vertex, arrow and projective counts #

theorem MagnitudeConjecture.ARCount.surplus_eq_counts {ι : Type u} [Fintype ι] (a : ι → ι → ℕ) (P : ι → Prop) [DecidablePred P] :

The surplus is twice the vertex count, less arrows and twice the projective count.

theorem MagnitudeConjecture.GradedInterval.surplus_error_of_exact_counts (N Nm p pm m : ℕ) (a am W C : ℤ) (hN : ↑Nm = ↑N * (↑m + 1) - W) (ha : |am - (↑m + 1) * a| ≤ C) (hp : pm = p * (m + 1)) :
|2 * ↑Nm - am - 2 * ↑pm - (↑m + 1) * (2 * ↑N - a - 2 * ↑p)| ≤ 2 * |W| + C

Exact object and simple counts together with the arrow error give the surplus error, with a fixed support-width correction.