Subgroup.finiteIndex_of_leftCoset_cover_const

∀ {G : Type u_1} [inst : Group G] {ι : Type u_2} {s : Finset ι} {H : Subgroup G} {g : ι → G},
  ⋃ i ∈ s, g i • ↑H = Set.univ → H.FiniteIndex

If H is a subgroup of G and G is the union of a finite family of left cosets of H then H has finite index.

Defined in: Mathlib.GroupTheory.CosetCover
Cited by: 2 results in Mathlib
Foundations: Depth 99 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: Group

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