reserve A for QC-alphabet;
reserve k,n,m for Nat;
reserve P for QC-pred_symbol of A;
reserve F for Element of QC-WFF(A);
reserve Q for QC-pred_symbol of A;
reserve F, G for (Element of QC-WFF(A)), s for FinSequence;
reserve p for Element of QC-WFF(A);
reserve F for Element of QC-WFF(A);
reserve p for Element of QC-WFF(A);
reserve j,k for Nat;
reserve k for Nat;
reserve s,t,u,v for QC-symbol of A;

theorem Th29:
  s <= t & t < v implies s < v
by Th21,Th25;
