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

theorem Th350:
  for p being Real holds p <= q
  implies ].-infty,q.] \ {p} = ].-infty,p.[ \/ ].p,q.]
proof
  let p be Real;
  p in REAL by XREAL_0:def 1;
  hence thesis by Th315,XXREAL_0:12;
end;
