Documentation

Q2Presentation.Lifting.Obstruction

theorem Q2Presentation.Lifting.conjEndN_mul_mem {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (y s : Yt.Y) (hs : s ∈ E.N) :
conjEndN E (y * s) = conjEndN E y

Kernel conjugations are invisible to the shadow operators.

theorem Q2Presentation.Lifting.foxShadow_perturb_eq {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (q : Marking Yt.Y) (n : Gen → ↥E.N) (m : Gen → NAdd E) (w : GExpr) :
foxShadow E (perturb E q n) m w = foxShadow E q m w

Row invariance under kernel perturbation: shadows at a perturbed marking agree with shadows at the base.

theorem Q2Presentation.Lifting.rowMap_perturb_eq {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (q : Marking Yt.Y) (n : Gen → ↥E.N) :
rowMap E (perturb E q n) = rowMap E q

The row map only depends on the marking through its kernel cosets.

theorem Q2Presentation.Lifting.compat_eq_perturb {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (q q' : Marking Yt.Y) (h : ∀ (a : Gen), (QuotientGroup.mk' E.N) (q a) = (QuotientGroup.mk' E.N) (q' a)) :
∃ (n : Gen → ↥E.N), q' = perturb E q n

Two kernel-compatible markings differ by a kernel perturbation.

theorem Q2Presentation.Lifting.defect_mem_of_lift {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (F : BoundaryFrame Yt) (g : boundaryFramedSurj boundaryPackage_GammaA (TorsorProgram.quotientFramedTarget Yt E.N ⋯ ⋯) (TorsorProgram.quotientFrame Yt E.N ⋯ ⋯ F)) (q : Marking Yt.Y) (hq : ∀ (a : Gen), (QuotientGroup.mk' E.N) (q a) = (ProfiniteGrp.Hom.hom (↑g).hom) (gammaGen a)) (w : GExpr) (hw1 : (w.eval fun (a : Gen) => (ProfiniteGrp.Hom.hom (↑g).hom) (gammaGen a)) = 1) :
w.eval q ∈ E.N

Relator defects of kernel-compatible markings lie in the kernel.

theorem Q2Presentation.Lifting.defectPair_perturb {Yt : BoundaryFramedTarget} [Finite Yt.Y] (E : ElementaryKernel Yt) (F : BoundaryFrame Yt) (g : boundaryFramedSurj boundaryPackage_GammaA (TorsorProgram.quotientFramedTarget Yt E.N ⋯ ⋯) (TorsorProgram.quotientFrame Yt E.N ⋯ ⋯ F)) (q : Marking Yt.Y) (hq : ∀ (a : Gen), (QuotientGroup.mk' E.N) (q a) = (ProfiniteGrp.Hom.hom (↑g).hom) (gammaGen a)) (n : Gen → ↥E.N) (hq' : ∀ (a : Gen), (QuotientGroup.mk' E.N) (perturb E q n a) = (ProfiniteGrp.Hom.hom (↑g).hom) (gammaGen a)) :
defectPair E F g (perturb E q n) hq' = defectPair E F g q hq + (rowMap E q) fun (a : Gen) => Additive.ofMul (n a)

Perturbation shifts the defect pair by a row value.

The obstruction space of g: the row-map cokernel at the base marking.

Equations
  • One or more equations did not get rendered due to their size.
Instances For
    Equations
    • One or more equations did not get rendered due to their size.
    Equations
    • One or more equations did not get rendered due to their size.

    The obstruction class of g.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For