reserve x1,x2,y1,a,b,c for Real;

theorem
  for p be Real st p >= 1 for lp be non empty NORMSTR st lp = NORMSTR (#
    the_set_of_RealSequences_l^p, Zero_(the_set_of_RealSequences_l^p,
    Linear_Space_of_RealSequences), Add_(the_set_of_RealSequences_l^p,
    Linear_Space_of_RealSequences), Mult_(the_set_of_RealSequences_l^p,
Linear_Space_of_RealSequences), l_norm^p #) holds lp is RealNormSpace by Th9
