let p, r, s be ExtReal; :: thesis: ( r <= s implies ].r,+infty.[ \ [.p,s.] = ].r,p.[ \/ ].s,+infty.[ )
p <= +infty by XXREAL_0:3;
hence ( r <= s implies ].r,+infty.[ \ [.p,s.] = ].r,p.[ \/ ].s,+infty.[ ) by Th309; :: thesis: verum