theorem
f in Lp_Functions (M,k) & g in a.e-eq-class_Lp(f,M,k) implies
  a.e-eq-class_Lp(f,M,k) = a.e-eq-class_Lp(g,M,k)
proof
   assume that
A1: f in Lp_Functions(M,k) and
A2: g in a.e-eq-class_Lp(f,M,k);
   ex E be Element of S st M.(E`) = 0 & dom f = E & f is E-measurable
      by A1,Th35;
   hence thesis by Th41,A2,Th37;
end;
