d = 1 universality: every VC-1 class compresses at kernel size one, with no side information. No finiteness, no distinguished member, no chain hypothesis. Twist the class by any member to place β
in it; there the VC bound makes co-member points comparable in the membership order, so every label set is a finite chain; anchor at its maximum, reconstruct with interConvention, and transport the scheme back with the same kernels.
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] {π : Set (Set Ξ±)},
StructuralIgnorance.vcBounded π 1 β StructuralIgnorance.HasKernelScheme π 1- DeclStructuralIgnorance.hasKernelScheme_one_of_vcBounded_oneDeclaration kindtheorem
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] {π : Set (Set Ξ±)}, StructuralIgnorance.vcBounded π 1 β StructuralIgnorance.HasKernelScheme π 1 - DeclStructuralIgnorance.vcBounded_twistClassDeclaration kindtheorem
VC bounds are twist-invariant (the direction needed for normalization).
β {Ξ± : Type u_1} [DecidableEq Ξ±] {π : Set (Set Ξ±)} {d : β}, StructuralIgnorance.vcBounded π d β β (Sβ : Set Ξ±), StructuralIgnorance.vcBounded (StructuralIgnorance.twistClass π Sβ) d - DeclStructuralIgnorance.SetShatters.of_twistClassDeclaration kindtheorem
Shattering transports from the twisted class back to the original: the witnesses untwist, and the patterns correspond through the involution
C β¦ C β (B β© Sβ).β {Ξ± : Type u_1} [DecidableEq Ξ±] {π : Set (Set Ξ±)} {Sβ : Set Ξ±} {B : Finset Ξ±}, StructuralIgnorance.SetShatters (StructuralIgnorance.twistClass π Sβ) B β StructuralIgnorance.SetShatters π B - DeclStructuralIgnorance.memOrder_total_of_vcBounded_oneDeclaration kindtheorem
With the empty set in the class, a VC bound of one makes any two points of a common member comparable in the membership order: otherwise the four assembled patterns shatter the pair.
β {Ξ± : Type u_1} [DecidableEq Ξ±] {π : Set (Set Ξ±)}, StructuralIgnorance.vcBounded π 1 β β β π β β {a b : Ξ±}, (β S β π, a β S β§ b β S) β StructuralIgnorance.memOrder π a b β¨ StructuralIgnorance.memOrder π b a - DeclStructuralIgnorance.isKernel_interConvention_anchorDeclaration kindtheorem
The anchor leg of the intersection convention: a maximum of the label set in the membership order is a size-1 kernel. The upper inclusion comes from the realizing member, the lower from maximality.
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] {π : Set (Set Ξ±)} {A T : Finset Ξ±}, StructuralIgnorance.IsSample π A T β β {x : Ξ±}, x β T β (β a β T, StructuralIgnorance.memOrder π a x) β StructuralIgnorance.IsKernel (StructuralIgnorance.interConvention π) 1 A T {x} - DeclStructuralIgnorance.IsSample.subsetDeclaration kindtheorem
Realizable label patterns are supported inside their window.
β {Ξ± : Type u_1} {π : Set (Set Ξ±)} {A T : Finset Ξ±}, StructuralIgnorance.IsSample π A T β T β A - DeclStructuralIgnorance.exists_memOrder_max_of_totalDeclaration kindtheorem
A finite nonempty set on which the membership order is total has a maximum.
β {Ξ± : Type u_1} {π : Set (Set Ξ±)} {T : Finset Ξ±}, (β a β T, β b β T, StructuralIgnorance.memOrder π a b β¨ StructuralIgnorance.memOrder π b a) β T.Nonempty β β x β T, β a β T, StructuralIgnorance.memOrder π a x - DeclStructuralIgnorance.memOrder_transDeclaration kindtheorem
β {Ξ± : Type u_1} {π : Set (Set Ξ±)} {a b c : Ξ±}, StructuralIgnorance.memOrder π a b β StructuralIgnorance.memOrder π b c β StructuralIgnorance.memOrder π a c - DeclStructuralIgnorance.memOrder_reflDeclaration kindtheorem
β {Ξ± : Type u_1} (π : Set (Set Ξ±)) (a : Ξ±), StructuralIgnorance.memOrder π a a - DeclStructuralIgnorance.empty_mem_twistClassDeclaration kindtheorem
Twisting by a member places the empty set in the class.
β {Ξ± : Type u_1} {π : Set (Set Ξ±)} {Sβ : Set Ξ±}, Sβ β π β β β StructuralIgnorance.twistClass π Sβ - DeclStructuralIgnorance.HasKernelScheme.of_twistClassDeclaration kindtheorem
Kernel schemes transport back through a twist, with the same kernels.
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] {π : Set (Set Ξ±)} {Sβ : Set Ξ±} {k : β}, StructuralIgnorance.HasKernelScheme (StructuralIgnorance.twistClass π Sβ) k β StructuralIgnorance.HasKernelScheme π kStructuralIgnorance.ConventionStructuralIgnorance.HasKernelSchemeStructuralIgnorance.IsKernelStructuralIgnorance.IsSampleStructuralIgnorance.baseLabelsStructuralIgnorance.twistClassStructuralIgnorance.twistConventionUses
- DeclStructuralIgnorance.set_symmDiff_inter_rightDeclaration kindtheorem
β {Ξ± : Type u_1} (s t u : Set Ξ±), symmDiff s t β© u = symmDiff (s β© u) (t β© u) - DeclStructuralIgnorance.finset_inter_symmDiffDeclaration kindtheorem
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] (Z T F : Finset Ξ±), Z β© symmDiff T F = symmDiff (Z β© T) (Z β© F) - DeclStructuralIgnorance.IsSample.twistDeclaration kindtheorem
Realizability transports through the twist, with the label set twisted inside the window.
β {Ξ± : Type u_1} [inst : DecidableEq Ξ±] {π : Set (Set Ξ±)} {A T : Finset Ξ±}, StructuralIgnorance.IsSample π A T β β (Sβ : Set Ξ±), StructuralIgnorance.IsSample (StructuralIgnorance.twistClass π Sβ) A (symmDiff T (StructuralIgnorance.baseLabels Sβ A)) - DeclStructuralIgnorance.coe_baseLabelsDeclaration kindtheorem
β {Ξ± : Type u_1} (Sβ : Set Ξ±) (Z : Finset Ξ±), β(StructuralIgnorance.baseLabels Sβ Z) = βZ β© Sβ - Hypothesish
StructuralIgnorance.vcBounded π 1
- DefinitionStructuralIgnorance.Conventiondef
A reconstruction rule: from a kept labeled pair β kernel points and their 1-labeled part β to a total hypothesis. Total by convention; only values on realizable pairs matter.
Type u_2 β Type u_2
- DefinitionStructuralIgnorance.HasKernelSchemedef
A kernel scheme of size
kwith no side information: one reconstruction rule under which every realizable sample contains a generating kernel of at mostkpoints (LittlestoneβWarmuth 1986, in compression-map-free form).{Ξ± : Type u_1} β [DecidableEq Ξ±] β Set (Set Ξ±) β β β Prop - DefinitionStructuralIgnorance.IsKerneldef
Οregenerates the sample(A, T)from the kernelZ: the kernel is kept inside the sample, has at mostkpoints, and the reconstructed hypothesis meetsAin exactlyT.{Ξ± : Type u_1} β [DecidableEq Ξ±] β StructuralIgnorance.Convention Ξ± β β β Finset Ξ± β Finset Ξ± β Finset Ξ± β Prop - DefinitionStructuralIgnorance.IsSampledef
The labeled window
(A, T)is realizable inπ: some member meetsAin exactlyT. Points ofTare labeled 1, points ofA \ Tare labeled 0 (LittlestoneβWarmuth 1986, realizable samples).{Ξ± : Type u_1} β Set (Set Ξ±) β Finset Ξ± β Finset Ξ± β Prop - DefinitionStructuralIgnorance.SetShattersdef
The class
πshatters the finite setB: every sub-pattern ofBis realized by a member.Set-grammar port ofFinset.Shatters(MathlibCombinatorics.SetFamily.Shatter).{Ξ± : Type u_1} β Set (Set Ξ±) β Finset Ξ± β Prop - DefinitionStructuralIgnorance.baseLabelsdef
The part of a finite window lying in the base set.
{Ξ± : Type u_1} β Set Ξ± β Finset Ξ± β Finset Ξ± - DefinitionStructuralIgnorance.interConventiondef
Reconstruction by intersection: the hypothesis is the intersection of all members containing the kernel's 1-labeled part. Improper β the output need not be a member β which is what dense chains require; the kernel's point set is not consulted beyond its labels.
{Ξ± : Type u_1} β Set (Set Ξ±) β StructuralIgnorance.Convention Ξ± - DefinitionStructuralIgnorance.memOrderdef
The membership order of a class:
alies belowbwhen every member containingbcontainsa.{Ξ± : Type u_1} β Set (Set Ξ±) β Ξ± β Ξ± β Prop - DefinitionStructuralIgnorance.twistClassdef
The class relabeled by symmetric difference with a base set.
{Ξ± : Type u_1} β Set (Set Ξ±) β Set Ξ± β Set (Set Ξ±) - DefinitionStructuralIgnorance.twistConventiondef
The conjugated convention: untwist the kernel's labels, reconstruct in the twisted class, twist the hypothesis back.
{Ξ± : Type u_1} β [DecidableEq Ξ±] β Set Ξ± β StructuralIgnorance.Convention Ξ± β StructuralIgnorance.Convention Ξ± - DefinitionStructuralIgnorance.vcBoundeddef
VC bound in
Setgrammar: no shattered set exceedsdpoints (the port ofFinset.vcDim β€ d, MathlibCombinatorics.SetFamily.Shatter).{Ξ± : Type u_1} β Set (Set Ξ±) β β β Prop
Verification
- Replay
- accepted
- Axioms
- Classical.choiceQuot.soundpropext
- Statement identity
- not-applicable
- Substrate
- Lean 4 kernel v4.31.0
- Dictionary pin
- design-lab@5802df4 Β· initial
- Frozen export
- 1641f3634b64
- Verified
- 2026-09-24T00:00:00Z