OAI/CategoryTheory/Thomason/Simplicial/RealizationCellClosure.lean
56 declarations, 0 contain sorry, 0 declared as axioms
Nondegenerate barycentric coordinates of a realization point
- abbrev
OAI.Thomason.Construction.RealizationPrism.NondegenerateCoordinatesline 24Source documentation
A nondegenerate simplex with its barycentric coordinates.
abbrev NondegenerateCoordinates (K : SSet.{0}) := … - def
OAI.Thomason.Construction.RealizationPrism.normalizeSimplexline 28Source documentation
Remove degeneracies from a simplex and push forward its barycentric coordinates.
def normalizeSimplex (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (n+1))) : NondegenerateCoordinates K := …Mentions: OAI.Thomason.Construction.RealizationPrism.NondegenerateCoordinates
- theorem
OAI.Thomason.Construction.RealizationPrism.normalizeSimplex_of_representationline 33Source documentation
Any nondegenerate epimorphic presentation computes the same normalization.
theorem normalizeSimplex_of_representation (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (n+1))) (c : K.N) (f : SimplexCategory.mk n ⟶ .mk c.dim) [Epi f] (h : K.map f.op c.simplex = s) : normalizeSimplex K s x = ⟨c, StdSimplex.map f.toOrderHom x⟩ := by …Mentions: OAI.Thomason.Construction.RealizationPrism.normalizeSimplex
- theorem
OAI.Thomason.Construction.RealizationPrism.normalizeSimplex_epiline 51Source documentation
Removing degeneracies commutes with an epimorphic simplex operator.
theorem normalizeSimplex_epi (K : SSet.{0}) {m n : ℕ} (f : SimplexCategory.mk m ⟶ .mk n) [Epi f] (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (m+1))) : normalizeSimplex K (K.map f.op s) x = normalizeSimplex K s (StdSimplex.map f.toOrderHom x) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.normalizeSimplex
- def
OAI.Thomason.Construction.RealizationPrism.normalizeSupportedline 69Source documentation
First discard zero coordinates, then remove degeneracies from the supported simplex.
def normalizeSupported (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (n+1))) : NondegenerateCoordinates K := …Mentions: OAI.Thomason.Construction.RealizationPrism.NondegenerateCoordinates
- theorem
OAI.Thomason.Construction.RealizationPrism.normalizeSupported_naturalityline 76Source documentation
The supported nondegenerate coordinates are invariant under all simplex operators.
theorem normalizeSupported_naturality (K : SSet.{0}) {m n : ℕ} (f : SimplexCategory.mk m ⟶ .mk n) (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (m+1))) : normalizeSupported K (K.map f.op s) x = normalizeSupported K s (StdSimplex.map f.toOrderHom x) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.normalizeSupported
- def
OAI.Thomason.Construction.RealizationPrism.normalizationCoconeline 106Source documentation
Nondegenerate coordinates form a cocone of sets over all realization simplices.
def normalizationCocone (K : SSet.{0}) : Cocone (diagram K ⋙ forget TopCat) where …Mentions: OAI.Thomason.Construction.RealizationPrism.diagram
- def
OAI.Thomason.Construction.RealizationPrism.normalizationline 121Source documentation
The nondegenerate coordinates of an actual realization point.
def normalization (K : SSet.{0}) : SSet.toTop.obj K → NondegenerateCoordinates K := …Mentions: OAI.Thomason.Construction.RealizationPrism.NondegenerateCoordinates
- theorem
OAI.Thomason.Construction.RealizationPrism.normalization_legline 124 - def
OAI.Thomason.Construction.RealizationPrism.denormalizeline 148Source documentation
Evaluate a nondegenerate simplex with specified barycentric coordinates.
def denormalize (K : SSet.{0}) (p : NondegenerateCoordinates K) : SSet.toTop.obj K := …Mentions: OAI.Thomason.Construction.RealizationPrism.NondegenerateCoordinates
- theorem
OAI.Thomason.Construction.RealizationPrism.denormalize_normalizeSimplexline 151 - theorem
OAI.Thomason.Construction.RealizationPrism.denormalize_normalizeSupportedline 160 - theorem
OAI.Thomason.Construction.RealizationPrism.normalization_simplexPointline 170 - theorem
OAI.Thomason.Construction.RealizationPrism.denormalize_normalizationline 180Source documentation
The intrinsic normal coordinates reconstruct every actual realization point.
theorem denormalize_normalization (K : SSet.{0}) (x : SSet.toTop.obj K) : denormalize K (normalization K x) = x := by …Mentions: OAI.Thomason.Construction.RealizationPrism.denormalize, OAI.Thomason.Construction.RealizationPrism.normalization
- theorem
OAI.Thomason.Construction.RealizationPrism.normalization_injectiveline 186Source documentation
Distinct realization points have distinct intrinsic nondegenerate coordinates.
theorem normalization_injective (K : SSet.{0}) : Function.Injective (normalization K) := …Mentions: OAI.Thomason.Construction.RealizationPrism.normalization
- theorem
OAI.Thomason.Construction.RealizationPrism.normalizeSupported_of_full_supportline 191Source documentation
With no zero coordinates the support normalization agrees with degeneracy normalization.
theorem normalizeSupported_of_full_support (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (x : StdSimplex ℝ (Fin (n+1))) (hx : ∀ i, x.weights i ≠ 0) : normalizeSupported K s x = normalizeSimplex K s x := by …Mentions: OAI.Thomason.Construction.RealizationPrism.normalizeSupported, OAI.Thomason.Construction.RealizationPrism.normalizeSimplex
- theorem
OAI.Thomason.Construction.RealizationPrism.normalization_nondegenerate_interiorline 208Source documentation
Interior points of a nondegenerate simplex have precisely that simplex's coordinates.
theorem normalization_nondegenerate_interior (K : SSet.{0}) (s : K.N) (x : StdSimplex ℝ (Fin (s.dim+1))) (hx : ∀ i, x.weights i ≠ 0) : normalization K (simplexPoint K s.simplex x) = ⟨s, x⟩ := by …Mentions: OAI.Thomason.Construction.RealizationPrism.normalization, OAI.Thomason.Construction.RealizationPrism.simplexPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.normalizeSimplex_continuousline 234Source documentation
Degeneracy normalization on a fixed simplex is continuous into the disjoint union.
theorem normalizeSimplex_continuous (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : Continuous (normalizeSimplex K s) := …Mentions: OAI.Thomason.Construction.RealizationPrism.normalizeSimplex
- theorem
OAI.Thomason.Construction.RealizationPrism.nondegenerateCoordinates_t2Spaceline 238 - theorem
OAI.Thomason.Construction.RealizationPrism.simplexPoint_fiber_eqline 245Source documentation
A point fibre on a parameter simplex is a finite union of compact affine images.
theorem simplexPoint_fiber_eq (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (z : SSet.toTop.obj K) : (simplexPoint K s) ⁻¹' {z} = ⋃ i : FaceIndex n, (StdSimplex.map i.2.toOrderHom) '' ((normalizeSimplex K (K.map i.2.op s)) ⁻¹' {normalization K z}) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint, OAI.Thomason.Construction.RealizationPrism.FaceIndex, OAI.Thomason.Construction.RealizationPrism.normalizeSimplex, OAI.Thomason.Construction.RealizationPrism.normalization
- theorem
OAI.Thomason.Construction.RealizationPrism.simplexPoint_fiber_isClosedline 271Source documentation
Individual point fibres are closed on every barycentric parameter simplex.
theorem simplexPoint_fiber_isClosed (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) (z : SSet.toTop.obj K) : IsClosed ((simplexPoint K s) ⁻¹' {z}) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.realization_t1Spaceline 284Source documentation
Every actual geometric realization is a T₁ space.
theorem realization_t1Space (K : SSet.{0}) : T1Space (SSet.toTop.obj K) where … - theorem
OAI.Thomason.Construction.RealizationPrism.simplexCarrier_range_finiteline 319Source documentation
Only finitely many supported simplex carriers occur in one parameter simplex.
theorem simplexCarrier_range_finite (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : Set.Finite (Set.range (simplexCarrier K s)) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexCarrier
- theorem
OAI.Thomason.Construction.RealizationPrism.isClosed_of_carrier_injOnline 331Source documentation
A set containing at most one point in each carrier is closed.
theorem isClosed_of_carrier_injOn (K : SSet.{0}) (S : Set (SSet.toTop.obj K)) (hS : Set.InjOn (carrier K) S) : IsClosed S := by …Mentions: OAI.Thomason.Construction.RealizationPrism.carrier
- theorem
OAI.Thomason.Construction.RealizationPrism.isDiscrete_of_carrier_injOnline 351Source documentation
Such a set is also discrete, since each of its subsets has the same carrier property.
theorem isDiscrete_of_carrier_injOn (K : SSet.{0}) (S : Set (SSet.toTop.obj K)) (hS : Set.InjOn (carrier K) S) : IsDiscrete S := by …Mentions: OAI.Thomason.Construction.RealizationPrism.carrier
- theorem
OAI.Thomason.Construction.RealizationPrism.compact_carriers_finiteline 358Source documentation
Every compact subset of realization meets only finitely many supported simplex carriers.
theorem compact_carriers_finite (K : SSet.{0}) (C : Set (SSet.toTop.obj K)) (hC : IsCompact C) : Set.Finite (carrier K '' C) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.carrier
- theorem
OAI.Thomason.Construction.RealizationPrism.carrier_finiteline 395Source documentation
Every intrinsic carrier is generated by one simplex, hence is a finite simplicial set.
theorem carrier_finite (K : SSet.{0}) (x : SSet.toTop.obj K) : SSet.Finite (carrier K x : SSet) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.carrier
- def
OAI.Thomason.Construction.RealizationPrism.compactSubcomplexline 403Source documentation
The finite subcomplex generated by all carriers met by a compact subset.
def compactSubcomplex (K : SSet.{0}) (C : Set (SSet.toTop.obj K)) : K.Subcomplex := … - theorem
OAI.Thomason.Construction.RealizationPrism.compactSubcomplex_finiteline 406 - theorem
OAI.Thomason.Construction.RealizationPrism.compactSubcomplex_containsline 414Source documentation
The compact subset lies in the realization of its finite carrier subcomplex.
theorem compactSubcomplex_contains (K : SSet.{0}) (C : Set (SSet.toTop.obj K)) : C ⊆ Set.range (SSet.toTop.map (compactSubcomplex K C).ι).hom := by …Mentions: OAI.Thomason.Construction.RealizationPrism.compactSubcomplex
- theorem
OAI.Thomason.Construction.RealizationPrism.compact_map_factorsline 422Source documentation
Every continuous map from a compact space into realization factors continuously through the realization of a finite simplicial subcomplex.
theorem compact_map_factors {X : Type} [TopologicalSpace X] [CompactSpace X] (K : SSet.{0}) (f : C(X, SSet.toTop.obj K)) : ∃ (A : K.Subcomplex), SSet.Finite (A : SSet) ∧ ∃ g : C(X, SSet.toTop.obj (A : SSet)), (SSet.toTop.map A.ι).hom.comp g = f := by … - theorem
OAI.Thomason.Construction.RealizationPrism.based_cube_factorsline 459Source documentation
Every positive-dimensional based cube in realization factors through a finite subcomplex, with its entire boundary still constant at a lifted basepoint.
theorem based_cube_factors (K : SSet.{0}) {x : SSet.toTop.obj K} (n : ℕ) (p : GenLoop (Fin (n+1)) (SSet.toTop.obj K) x) : ∃ (A : K.Subcomplex), SSet.Finite (A : SSet) ∧ ∃ (a : SSet.toTop.obj (A : SSet)), (SSet.toTop.map A.ι).hom a = x ∧ ∃ q : GenLoop (Fin (n+1)) (SSet.toTop.obj (A : SSet)) a, ∀ t, (SSet.toTop.map A.ι).hom (q t) = p t := by … - theorem
OAI.Thomason.Construction.RealizationPrism.based_homotopy_factorsline 479Source documentation
A relative homotopy of based cubes has a single finite-subcomplex factorization, including both endpoint cubes and the fixed boundary.
theorem based_homotopy_factors (K : SSet.{0}) {x : SSet.toTop.obj K} (n : ℕ) {p q : GenLoop (Fin (n+1)) (SSet.toTop.obj K) x} (H : p.val.HomotopyRel q.val (Cube.boundary (Fin (n+1)))) : ∃ (A : K.Subcomplex), SSet.Finite (A : SSet) ∧ ∃ (a : SSet.toTop.obj (A : SSet)), (SSet.toTop.map A.ι).hom a = x ∧ ∃ (p' q' : GenLoop (Fin (n+1)) (SSet.toTop.obj (A : SSet)) a) (H' : p'.val.HomotopyRel q'.val (Cube.boundary (Fin (n+1)))), (∀ t, (SSet.toTop.map A.ι).hom (p' t) = p t) ∧ (∀ t, (SSet.toTop.map A.ι).hom (q' t) = q t) ∧ (∀ z, (SSet.toTop.map A.ι).hom (H' z) = H z) := by … - theorem
OAI.Thomason.Construction.RealizationPrism.compact_square_factorsline 536Source documentation
A continuous compact lifting problem over a realized simplicial map factors through one map between finite simplicial subcomplexes. The lifted square still commutes exactly, including any prescribed boundary values.
theorem compact_square_factors {P Q : Type} [TopologicalSpace P] [CompactSpace P] [TopologicalSpace Q] [CompactSpace Q] {K L : SSet.{0}} (f : K ⟶ L) (u : C(P, Q)) (a : C(P, SSet.toTop.obj K)) (b : C(Q, SSet.toTop.obj L)) (h : (SSet.toTop.map f).hom.comp a = b.comp u) : ∃ (A : K.Subcomplex) (B : L.Subcomplex), SSet.Finite (A : SSet) ∧ SSet.Finite (B : SSet) ∧ ∃ (g : (A : SSet) ⟶ (B : SSet)) (a' : C(P, SSet.toTop.obj (A : SSet))) (b' : C(Q, SSet.toTop.obj (B : SSet))), g ≫ B.ι = A.ι ≫ f ∧ (SSet.toTop.map A.ι).hom.comp a' = a ∧ … - def
OAI.Thomason.Construction.RealizationPrism.supportFaceIndexline 611 - def
OAI.Thomason.Construction.RealizationPrism.matchingFacePairsline 616Source documentation
Pairs of face points whose nondegenerate coordinate descriptions agree.
def matchingFacePairs (K : SSet.{0}) {n m : ℕ} (s : K.obj (.op (.mk n))) (t : K.obj (.op (.mk m))) (B : Set (StdSimplex ℝ (Fin (n+1)))) (i : FaceIndex n) (j : FaceIndex m) : Set (StdSimplex ℝ (Fin (i.1.val+1)) × StdSimplex ℝ (Fin (j.1.val+1))) := …Mentions: OAI.Thomason.Construction.RealizationPrism.FaceIndex
- theorem
OAI.Thomason.Construction.RealizationPrism.matchingFacePairs_isClosedline 623 - theorem
OAI.Thomason.Construction.RealizationPrism.simplexPoint_preimage_imageline 633Source documentation
Equality of points from two parameter simplices is detected by finitely many face pairs.
theorem simplexPoint_preimage_image (K : SSet.{0}) {n m : ℕ} (s : K.obj (.op (.mk n))) (t : K.obj (.op (.mk m))) (B : Set (StdSimplex ℝ (Fin (n+1)))) : (simplexPoint K t) ⁻¹' ((simplexPoint K s) '' B) = ⋃ ij : FaceIndex n × FaceIndex m, (fun p => StdSimplex.map ij.2.2.toOrderHom p.2) '' matchingFacePairs K s t B ij.1 ij.2 := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint, OAI.Thomason.Construction.RealizationPrism.FaceIndex, OAI.Thomason.Construction.RealizationPrism.matchingFacePairs
- theorem
OAI.Thomason.Construction.RealizationPrism.simplexPoint_isClosedMapline 661Source documentation
Each continuous simplex parameter map into realization is closed.
theorem simplexPoint_isClosedMap (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : IsClosedMap (simplexPoint K s) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.nondegenerateProjection_isClosedMapline 708 - theorem
OAI.Thomason.Construction.RealizationPrism.nondegenerateProjection_isQuotientMapline 728Source documentation
A finite realization has its actual quotient topology from its finitely many nondegenerate simplex parameter spaces.
theorem nondegenerateProjection_isQuotientMap (K : SSet.{0}) [K.Finite] : IsQuotientMap (nondegenerateProjection K) := …Mentions: OAI.Thomason.Construction.RealizationPrism.nondegenerateProjection
- theorem
OAI.Thomason.Construction.RealizationPrism.finite_realization_t2Spaceline 735Source documentation
Finite simplicial realizations are Hausdorff; no ambient separation assumption on arbitrary realizations is used.
theorem finite_realization_t2Space (K : SSet.{0}) [K.Finite] : T2Space (SSet.toTop.obj K) := by … - def
OAI.Thomason.Construction.RealizationPrism.monogenousPointline 787Source documentation
The parameter map onto the entire subcomplex generated by one simplex.
def monogenousPoint (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : C(StdSimplex ℝ (Fin (n+1)), SSet.toTop.obj (SSet.Subcomplex.ofSimplex s : SSet)) := … - theorem
OAI.Thomason.Construction.RealizationPrism.monogenousPoint_surjectiveline 792Source documentation
This map covers every point, including all degenerate representations.
theorem monogenousPoint_surjective (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : Function.Surjective (monogenousPoint K s) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.monogenousPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.monogenousPoint_isQuotientMapline 807Source documentation
The realization of a simplex-generated subcomplex is its closed topological quotient.
theorem monogenousPoint_isQuotientMap (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : IsQuotientMap (monogenousPoint K s) := …Mentions: OAI.Thomason.Construction.RealizationPrism.monogenousPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.monogenousPoint_inclusionline 813Source documentation
The original simplex parameter map factors through that quotient and the closed inclusion.
theorem monogenousPoint_inclusion (K : SSet.{0}) {n : ℕ} (s : K.obj (.op (.mk n))) : (SSet.toTop.map (SSet.Subcomplex.ofSimplex s).ι).hom.comp (monogenousPoint K s) = simplexPoint K s := by …Mentions: OAI.Thomason.Construction.RealizationPrism.monogenousPoint, OAI.Thomason.Construction.RealizationPrism.simplexPoint
- def
OAI.Thomason.Construction.RealizationPrism.fullSupportline 839Source documentation
The barycentric interior, expressed by its nonzero coordinates.
def fullSupport (n : ℕ) : Set (StdSimplex ℝ (Fin (n+1))) := …
- theorem
OAI.Thomason.Construction.RealizationPrism.fullSupport_isOpenline 842 - theorem
OAI.Thomason.Construction.RealizationPrism.normalization_dim_le_supportLenline 853 - theorem
OAI.Thomason.Construction.RealizationPrism.fullSupport_of_supportLen_geline 859 - theorem
OAI.Thomason.Construction.RealizationPrism.interior_simplexPoint_fiberline 872Source documentation
A point of a nondegenerate simplex interior has no other representative in that simplex, including on its boundary.
theorem interior_simplexPoint_fiber (K : SSet.{0}) (s : K.N) (x y : StdSimplex ℝ (Fin (s.dim+1))) (hx : x ∈ fullSupport s.dim) (hxy : simplexPoint K s.simplex y = simplexPoint K s.simplex x) : y = x := by …Mentions: OAI.Thomason.Construction.RealizationPrism.fullSupport, OAI.Thomason.Construction.RealizationPrism.simplexPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.interior_preimage_imageline 886Source documentation
The nondegenerate interior is saturated under the simplex quotient.
theorem interior_preimage_image (K : SSet.{0}) (s : K.N) : (simplexPoint K s.simplex) ⁻¹' ((simplexPoint K s.simplex) '' fullSupport s.dim) = fullSupport s.dim := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint, OAI.Thomason.Construction.RealizationPrism.fullSupport
- theorem
OAI.Thomason.Construction.RealizationPrism.closedMap_restrictPreimageline 914Source documentation
A closed map remains closed on the preimage of any target subspace.
theorem closedMap_restrictPreimage {X Y : Type} [TopologicalSpace X] [TopologicalSpace Y] {f : X → Y} (hf : IsClosedMap f) (S : Set Y) : IsClosedMap (S.restrictPreimage f) := by … - def
OAI.Thomason.Construction.RealizationPrism.cellInteriorHomeomorphline 930Source documentation
The open barycentric simplex is homeomorphic to the corresponding nondegenerate cell in the actual realization.
def cellInteriorHomeomorph (K : SSet.{0}) (s : K.N) : fullSupport s.dim ≃ₜ (simplexPoint K s.simplex '' fullSupport s.dim) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.fullSupport, OAI.Thomason.Construction.RealizationPrism.simplexPoint
- theorem
OAI.Thomason.Construction.RealizationPrism.fullSupport_denseline 972Source documentation
Every barycentric point is approached by points with all coordinates nonzero, by moving it towards the barycenter.
theorem fullSupport_dense (n : ℕ) : Dense (fullSupport n) := by …
Mentions: OAI.Thomason.Construction.RealizationPrism.fullSupport
- theorem
OAI.Thomason.Construction.RealizationPrism.closure_cellInteriorline 1000Source documentation
The closed characteristic simplex is the closure of its open cell. The statement is valid even when some boundary faces are identified.
theorem closure_cellInterior (K : SSet.{0}) (s : K.N) : closure (simplexPoint K s.simplex '' fullSupport s.dim) = Set.range (simplexPoint K s.simplex) := by …Mentions: OAI.Thomason.Construction.RealizationPrism.simplexPoint, OAI.Thomason.Construction.RealizationPrism.fullSupport