∀ {R : Type u_2} {a b : R} [inst : CommSemiring R] {A : Type u_1} [inst_1 : Ring A] [inst_2 : Algebra R A]
  (u : { u // u * u = a • 1 + b • u }), QuadraticAlgebra.re 0 • 1 + QuadraticAlgebra.im 0 • ↑u = 0