OAI/GroupTheory/PolycyclicRecognition/Finiteness/HomogeneousRepresentationCochains.lean

GitHub source file

13 declarations, 0 contain sorry, 0 declared as axioms

Controlled cochains as maps from the standard resolution

The coefficient at the identity of an equivariant group-ring-valued map recovers the scalar cochain. Conversely diagonal translation reconstructs that equivariant map, with finite support supplied by controlled-support estimates.

  1. def OAI.PolycyclicRecognition.homogeneousGroupRingValue line 19
  2. theorem OAI.PolycyclicRecognition.homogeneousGroupRingValue_coeff line 22
  3. theorem OAI.PolycyclicRecognition.homogeneousGroupRingValue_covariance line 26
  4. def OAI.PolycyclicRecognition.homogeneousGroupRingLinear line 34
  5. theorem OAI.PolycyclicRecognition.homogeneousGroupRingLinear_single line 39
  6. def OAI.PolycyclicRecognition.homogeneousRepresentationCochain line 45

    Source documentation

    The reconstructed values give an actual morphism of group representations.

    def homogeneousRepresentationCochain (c : controlledCochains R G n) :
        (Rep.standardComplex R G).X n ⟶ Rep.leftRegular R G :=
    …

    Mentions: OAI.PolycyclicRecognition.controlledCochains

  7. theorem OAI.PolycyclicRecognition.homogeneousRepresentationCochain_single_coeff line 61
  8. theorem OAI.PolycyclicRecognition.representationCochain_translate line 67
  9. theorem OAI.PolycyclicRecognition.representationCochain_controlled line 83

    Source documentation

    Evaluation at the identity has controlled support for every equivariant map from the homogeneous resolution.

    theorem representationCochain_controlled
        (F : (Rep.standardComplex R G).X n ⟶ Rep.leftRegular R G) :
        (fun x => (F.hom (MonoidAlgebra.single x 1)).coeff 1) ∈
          controlledCochains R G n := by
    …

    Mentions: OAI.PolycyclicRecognition.controlledCochains

  10. def OAI.PolycyclicRecognition.representationControlledCochain line 103

    Source documentation

    Scalar coefficient extraction, with its support obligation proved.

    def representationControlledCochain
        (F : (Rep.standardComplex R G).X n ⟶ Rep.leftRegular R G) :
        controlledCochains R G n :=
    …

    Mentions: OAI.PolycyclicRecognition.controlledCochains

  11. theorem OAI.PolycyclicRecognition.representationControlledCochain_homogeneous line 109
  12. theorem OAI.PolycyclicRecognition.homogeneousRepresentationCochain_controlled line 116
  13. def OAI.PolycyclicRecognition.homogeneousRepresentationCochainEquiv line 136

    Source documentation

    Controlled scalar cochains are exactly the equivariant cochains with coefficients in the left regular group ring.

    def homogeneousRepresentationCochainEquiv :
        controlledCochains R G n ≃ₗ[R]
          ((Rep.standardComplex R G).X n ⟶ Rep.leftRegular R G) where
    …

    Mentions: OAI.PolycyclicRecognition.controlledCochains