Counting distinct labels with shifts in a bounded window #
theorem
MagnitudeConjecture.GradedInterval.sigmaFinset_label_shift_injective
{ι : Type u_1}
(F : ι → Finset ℤ)
:
Function.Injective fun (a : (i : ι) × ↥(F i)) => (a.fst, ↑a.snd)
Forgetting membership proofs preserves distinct finite-label shifts.
theorem
MagnitudeConjecture.GradedInterval.card_le_of_label_shift_window
{ι : Type u_1}
{α : Type u_2}
[Fintype ι]
[Fintype α]
(label : α → ι)
(shift : α → ℤ)
(hinj : Function.Injective fun (a : α) => (label a, shift a))
(t : ℤ)
(h : ℕ)
(hwindow : ∀ (a : α), t ≤ shift a ∧ shift a ≤ t + ↑h)
:
Fintype.card α ≤ Fintype.card ι * (h + 1)
A family uniquely determined by a finite label and an integer shift has
at most card ι * (h + 1) members in a window of width h.