theorem Th36:
g in Lp_Functions(M,k) & g a.e.= f,M implies g in a.e-eq-class_Lp(f,M,k)
proof
   assume that
A1: g in Lp_Functions(M,k) and
A2: g a.e.= f,M;
   f a.e.= g,M by A2;
   hence g in a.e-eq-class_Lp(f,M,k) by A1;
end;
