let r be ext-real number ; :: thesis: for s being real number holds ].r,+infty .[ \ [.s,+infty .[ = ].r,s.[
let s be real number ; :: thesis: ].r,+infty .[ \ [.s,+infty .[ = ].r,s.[
s in REAL by XREAL_0:def 1;
hence ].r,+infty .[ \ [.s,+infty .[ = ].r,s.[ by Th195, XXREAL_0:9; :: thesis: verum