reserve x for set,
  p,q,r,s,t,u for ExtReal,
  g for Real,
  a for Element of ExtREAL;

theorem
  s <= p implies ].r,s.[ misses ].p,q.[
proof
  assume
A1: s <= p;
  let t be Real;
  assume t in ].r,s.[;
  then t <= s by Th4;
  then t <= p by A1,XXREAL_0:2;
  hence thesis by Th4;
end;
