Literal counts on a large conjunction majority fiber #
Within the product of three-state majority pairs, forcing d distinct signed
coordinates retains at most (2/3)^d of all inputs. This applies to any remaining
conjunction, without an independence assumption about its output.
theorem
Algebraic.Cutwidth.Aggregate.Geometry.Fiber.Conditional.three_pow_mul_card_le_of_forces
{E : Type u_1}
{V : Type u_2}
[Fintype E]
[Fintype V]
(edge : E → Entropy.SignedEdge V)
(disjoint : Function.Injective (endpoint edge))
(S : Finset V)
(bits : V → Bool)
(P : (V → Bool) → Prop)
[DecidablePred P]
(forces : ∀ (x : V → Bool), P x → ∀ v ∈ S, x v = bits v)
:
Fixing selected coordinates inside the majority event incurs a two-thirds cost per bit.
theorem
Algebraic.Cutwidth.Aggregate.Geometry.Fiber.Conditional.three_pow_mul_card_evalLiterals_le
{E : Type u_1}
{V : Type u_2}
[Fintype E]
[Fintype V]
[DecidableEq V]
(edge : E → Entropy.SignedEdge V)
(disjoint : Function.Injective (endpoint edge))
{L : Finset (V × Bool)}
{d : ℕ}
(many : d ≤ (Joint.literalVars L).card)
:
3 ^ d * {x : ↥(majorityInputs edge) | Joint.evalLiterals L ↑x = true}.card ≤ 2 ^ d * (majorityInputs edge).card
Any d distinct literals in a conjunction retain at most a (2/3)^d fraction.