Deriving a simplex volume bound from a cube cover
ProvedOAI.PiExponent.DeterminantContradiction.weighted_simplex_toReal_le_card_of_cube_covernumber-theoryopenai-pi-exponent-017
If the simplex is covered by a measurable set whose volume is the admissible-set cardinality, measure monotonicity yields the desired real-valued bound.
Preamble
import Definitions.Def_OAI_NumberTheory_PiExponent_Analysis_AnalyticAggregate_RemainderData import Definitions.Def_OAI_NumberTheory_PiExponent_WeightedSimplexRegion open scoped BigOperators Topology open Filter open OAI.PiExponent OAI.PiExponent.DeterminantContradiction open OAI.PiExponent.LiteralAnalytic
Formal statement
theorem OAI.PiExponent.DeterminantContradiction.weighted_simplex_toReal_le_card_of_cube_cover
(m : ℕ) (w : Fin m → ℝ) (T : ℝ) (hT : 0 ≤ T)
(hcover : weightedSimplexRegion w T ⊆ {x : Fin m → ℝ | ∃ a ∈ OAI.PiExponent.realWeightedSimplex w T, ∀ i, (a i : ℝ) ≤ x i ∧ x i < (a i : ℝ) + 1})
(hcubes : MeasureTheory.volume {x : Fin m → ℝ | ∃ a ∈ OAI.PiExponent.realWeightedSimplex w T, ∀ i, (a i : ℝ) ≤ x i ∧ x i < (a i : ℝ) + 1} =
((OAI.PiExponent.realWeightedSimplex w T).card : ENNReal)) :
ENNReal.toReal (MeasureTheory.volume (weightedSimplexRegion w T)) ≤
((OAI.PiExponent.realWeightedSimplex w T).card : ℝ) := by sorrySource