function benchmark_pearce()
  print("benchmark_pearce ... ")
  R, x = polynomial_ring(ZZ, "x")
  S, y = polynomial_ring(R, "y")
  T, z = polynomial_ring(S, "z")
  U, t = polynomial_ring(T, "t")
  V, u = polynomial_ring(U, "u")

  f = (x + y + 2z^2 + 3t^3 + 5u^5 + 1)^10
  g = (u + t + 2z^2 + 3y^3 + 5x^5 + 1)^10

  tt = @elapsed f*g
  println("$tt")
end

