reserve k,n for Element of NAT,
  a,Y for set,
  D,D1,D2 for non empty set,
  p,q for FinSequence of NAT;
reserve F,F1,G,G1,H,H1,H2 for CTL-formula;
reserve sq,sq9 for FinSequence;
reserve V for CTLModel;
reserve Kai for Function of atomic_WFF,the BasicAssign of V;
reserve f,f1,f2 for Function of CTL_WFF,the carrier of V;

theorem Th10:
  Evaluate(H1 'or' H2,Kai) = Evaluate(H1,Kai) 'or' Evaluate(H2,Kai )
proof
  Evaluate(H1 'or' H2,Kai) = 'not' Evaluate('not' H1 '&' 'not' H2,Kai) by Th5
    .= 'not' (Evaluate('not' H1,Kai) '&' Evaluate('not' H2,Kai)) by Th6
    .= 'not' (('not' Evaluate(H1,Kai)) '&' Evaluate('not' H2,Kai)) by Th5;
  hence thesis by Th5;
end;
