induction' e using Sym2.ind with a b
case h
α : Type u_1
β : Type u_2
γ : Type u_3
V : Type u_4
G H : SimpleGraph V
G' : G.Subgraph
e : Sym2 ↑G'.verts
⊢ e ∈ G'.coe.edgeSet ↔ e ∈ Sym2.map Subtype.val ⁻¹' G'.edgeSet
case h.h
α : Type u_1
β : Type u_2
γ : Type u_3
V : Type u_4
G H : SimpleGraph V
G' : G.Subgraph
a b : ↑G'.verts
⊢ s(a, b) ∈ G'.coe.edgeSet ↔ s(a, b) ∈ Sym2.map Subtype.val ⁻¹' G'.edgeSet