let p, q be ext-real number ; :: thesis: ( p <= q implies [.-infty ,q.] \ {p} = [.-infty ,p.[ \/ ].p,q.] )
-infty <= p by XXREAL_0:5;
hence ( p <= q implies [.-infty ,q.] \ {p} = [.-infty ,p.[ \/ ].p,q.] ) by Th316; :: thesis: verum