reserve A,B,p,q,r for Element of LTLB_WFF,
  M for LTLModel,
  j,k,n for Element of NAT,
  i for Nat,
  X for Subset of LTLB_WFF,
  F for finite Subset of LTLB_WFF,
  f for FinSequence of LTLB_WFF,
  g for Function of LTLB_WFF,BOOLEAN,
  x,y,z for set,
  P,Q,R for PNPair;

theorem Th4: TVERUM '&&' A is satisfiable implies A is satisfiable
  proof
    assume
    TVERUM '&&' A is satisfiable;
    then consider M,n such that
A1: (SAT M).[n,TVERUM '&&' A] = 1;
    (SAT M).[n,A] = 1 by LTLAXIO1:7,A1;
    hence A is satisfiable;
  end;
