let seq be ExtREAL_sequence; ( seq is bounded & seq is non-decreasing implies ( seq is convergent_to_finite_number & seq is convergent & lim seq = sup seq ) )
assume that
A1:
seq is bounded
and
A2:
seq is non-decreasing
; ( seq is convergent_to_finite_number & seq is convergent & lim seq = sup seq )
reconsider rseq = seq as Real_Sequence by A1, Th11;
A3:
seq is bounded_above
by A1, Def5;
then A4:
rseq is bounded_above
by Th12;
then
lim rseq = lim_inf rseq
by A2, RINFSUP1:91;
then
lim rseq = upper_bound rseq
by A2, RINFSUP1:66;
then A5:
lim seq = upper_bound rseq
by A2, A4, Th14;
rng seq is bounded_above
by A3, Def4;
hence
( seq is convergent_to_finite_number & seq is convergent & lim seq = sup seq )
by A2, A4, A5, Th1, Th14; verum