reserve X1,x,y,z for set,
  n,m for Nat,
  X for non empty set;
reserve A,B for Event of Borel_Sets,
  D for Subset of REAL;
reserve Q for QM_Str;
reserve A1 for Element of Obs Q;
reserve s for Element of Sts Q;
reserve E for Event of Borel_Sets;
reserve ASeq for SetSequence of Borel_Sets;
reserve Q for Quantum_Mechanics;
reserve s for Element of Sts Q;
reserve x1 for Element of X1;
reserve Inv for Function of X1,X1;
reserve p,q,r,p1,q1 for Element of Prop Q;

theorem Th1:
  for E st E = p`2` holds Meas(p`1,s).p`2 = 1 - Meas(p`1,s).E
proof
  let E such that
A1: E = p`2`;
  [#] Borel_Sets = REAL & REAL \ E = E` by PROB_1:def 7;
  hence thesis by A1,PROB_1:32;
end;
