let p, s be ext-real number ; :: thesis: ( p <= s implies [.p,+infty .] \ ].p,s.[ = {p} \/ [.s,+infty .] )
p <= +infty by XXREAL_0:3;
hence ( p <= s implies [.p,+infty .] \ ].p,s.[ = {p} \/ [.s,+infty .] ) by Th322; :: thesis: verum