OAI/Algebra/Finitistic/Selected/SelectedCountCohomology.lean
5 declarations, 0 contain sorry, 0 declared as axioms
- abbrev
OAI.LittleFinitistic.SelectedCountCohomology.countline 14Source documentation
The original summand with exactly r square-zero factors in the actual bar complex.
abbrev count (Y : FiniteSelectionFamily.S.{0}) (r : ℕ) := … - def
OAI.LittleFinitistic.SelectedCountCohomology.comparisonline 18Source documentation
Its exact standard integer-shift identification with the genuine derived iterate.
def comparison (Y : FiniteSelectionFamily.S.{0}) (r : ℕ) : (object Y r)⟦(r : ℤ)⟧ ≅ count Y r := …Mentions: OAI.LittleFinitistic.SelectedCountCohomology.count
- theorem
OAI.LittleFinitistic.SelectedCountCohomology.isZero_iffline 22 - theorem
OAI.LittleFinitistic.SelectedCountCohomology.boundedline 27 - theorem
OAI.LittleFinitistic.SelectedCountCohomology.nonzero_degreeline 45Source documentation
Every surviving iterate contributes a nonzero original count class in a homological degree at least r, with an explicit finite upper bound.
theorem nonzero_degree (Y : FiniteSelectionFamily.S.{0}) (r : ℕ) (h : ¬ IsZero (object Y r)) : ∃ n : ℕ, r ≤ n ∧ n ≤ r * (3 * length + 5) ∧ ¬ IsZero ((DerivedCategory.homologyFunctor (ModuleCat D) (-(n : ℤ))).obj (count Y r)) := by …Mentions: OAI.LittleFinitistic.SelectedCountCohomology.count