∀ {R : Type u_1} {M : Type u_4} [inst : Semiring R] [inst_1 : MulOneClass M],
  MonoidAlgebra.singleOneRingHom =
    { toFun := (↑(MonoidAlgebra.singleAddHom 1)).toFun, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }