∀ {R : Type u_1} {α : Type u_2} (G : SimpleGraph α) [inst : MulZeroOneClass R] [inst_1 : DecidableEq α]
  [inst_2 : DecidableRel G.Adj] {a : α} {e : Sym2 α}, e ∉ G.incidenceSet a → SimpleGraph.incMatrix R G a e = 0