reserve a,b,r for Real;
reserve A,B for non empty set;
reserve f,g,h for Element of PFuncs(A,REAL);
reserve u,v,w for VECTOR of RLSp_PFunctA;
reserve X for non empty set,
  x for Element of X,
  S for SigmaField of X,
  M for sigma_Measure of S,
  E,E1,E2 for Element of S,
  f,g,h,f1,g1 for PartFunc of X ,REAL;
reserve v,u for VECTOR of RLSp_L1Funct M;

theorem Th28:
  f a.e.= f,M
proof
  {} is Element of S by PROB_1:4;
  then consider E being Element of S such that
A1: E = {};
A2: f|E` = f|E`;
  M.E = 0 by A1,VALUED_0:def 19;
  hence thesis by A2;
end;
