let X be RealUnitarySpace; for g1, g2 being Point of X
for seq1, seq2 being sequence of X st seq1 is convergent & lim seq1 = g1 & seq2 is convergent & lim seq2 = g2 holds
( dist ((seq1 + seq2),(g1 + g2)) is convergent & lim (dist ((seq1 + seq2),(g1 + g2))) = 0 )
let g1, g2 be Point of X; for seq1, seq2 being sequence of X st seq1 is convergent & lim seq1 = g1 & seq2 is convergent & lim seq2 = g2 holds
( dist ((seq1 + seq2),(g1 + g2)) is convergent & lim (dist ((seq1 + seq2),(g1 + g2))) = 0 )
let seq1, seq2 be sequence of X; ( seq1 is convergent & lim seq1 = g1 & seq2 is convergent & lim seq2 = g2 implies ( dist ((seq1 + seq2),(g1 + g2)) is convergent & lim (dist ((seq1 + seq2),(g1 + g2))) = 0 ) )
assume
( seq1 is convergent & lim seq1 = g1 & seq2 is convergent & lim seq2 = g2 )
; ( dist ((seq1 + seq2),(g1 + g2)) is convergent & lim (dist ((seq1 + seq2),(g1 + g2))) = 0 )
then
( seq1 + seq2 is convergent & lim (seq1 + seq2) = g1 + g2 )
by Th3, Th13;
hence
( dist ((seq1 + seq2),(g1 + g2)) is convergent & lim (dist ((seq1 + seq2),(g1 + g2))) = 0 )
by Th24; verum