exact {
  mul_mem := hmul_mem
  one_mem := hone_mem
  inv_mem := hinv_mem
}
α : Type u_1
G : group α
hmul_mem : ∀ (a b : α), a ∈ whole_group → b ∈ whole_group → a * b ∈ whole_group
hone_mem : has_one.one ∈ whole_group
hinv_mem : ∀ (a : α), a ∈ whole_group → group.inv a ∈ whole_group
⊢ subgroup G whole_group
no goals