Module

Subgroup_exists_eq_mul_of_index_inf_eq.lean

Nyll.AlgebraicCurves.Foundations.Algebra.Subgroup_exists_eq_mul_of_index_inf_eq
3 declarations indexed from sourceView source ↗

Subgroup exists eq mul of index inf eq

Imports4
  • Mathlib.GroupTheory.GroupAction.Quotient
  • Mathlib.GroupTheory.Index
  • Mathlib.Data.Set.Card
  • Mathlib.Tactic.Group
Imported by2

Declarations

AlgebraicCurves.Foundations.Algebra.Proofs.Subgroup_exists_eq_mul_of_index_inf_eq.S11Orbit2.stabilizer_mk_one_eq
Source context 5 commands

Surrounding namespaces, section variables, and local commands at this declaration.

section ProofImplementation
namespace AlgebraicCurves.Foundations.Algebra.Proofs.Subgroup_exists_eq_mul_of_index_inf_eq
open MulAction
namespace S11Orbit2
variable {G : Type*} [Group G]
theorem stabilizer_mk_one_eq (H₁ H₂ : Subgroup G) :
    stabilizer H₂ ((1 : G) : G ⧸ H₁) = H₁.subgroupOf H₂
AlgebraicCurves.Foundations.Algebra.Proofs.Subgroup_exists_eq_mul_of_index_inf_eq.S11Orbit2.exists_eq_mul_of_index_inf_eq
Source context 5 commands

Surrounding namespaces, section variables, and local commands at this declaration.

section ProofImplementation
namespace AlgebraicCurves.Foundations.Algebra.Proofs.Subgroup_exists_eq_mul_of_index_inf_eq
open MulAction
namespace S11Orbit2
variable {G : Type*} [Group G]
theorem exists_eq_mul_of_index_inf_eq [Finite G] (H₁ H₂ : Subgroup G)
    (h : (H₁ ⊓ H₂).index = H₁.index * H₂.index) (g : G) :
    ∃ h₁ ∈ H₁, ∃ h₂ ∈ H₂, g = h₁ * h₂
Subgroup.exists_eq_mul_of_index_inf_eq
Source context 3 commands

Surrounding namespaces, section variables, and local commands at this declaration.

section ProofImplementation
namespace AlgebraicCurves.Foundations.Algebra.Proofs.Subgroup_exists_eq_mul_of_index_inf_eq
open MulAction
theorem _root_.Subgroup.exists_eq_mul_of_index_inf_eq {G : Type*} [Group G] [Finite G] (H₁ H₂ :
  Subgroup G) (h : (H₁ ⊓ H₂).index = H₁.index * H₂.index) (g : G) :
    ∃ h₁ ∈ H₁, ∃ h₂ ∈ H₂, g = h₁ * h₂