let r be ExtReal; :: thesis: for s being Real holds [.r,+infty.[ \ ].s,+infty.[ = [.r,s.]
let s be Real; :: thesis: [.r,+infty.[ \ ].s,+infty.[ = [.r,s.]
s in REAL by XREAL_0:def 1;
hence [.r,+infty.[ \ ].s,+infty.[ = [.r,s.] by Th196, XXREAL_0:9; :: thesis: verum