theorem
  seq1 is convergent & seq2 is convergent & lim(seq1-seq2)=0c implies
  lim seq1 = lim seq2
proof
  assume that
A1: seq1 is convergent & seq2 is convergent and
A2: lim(seq1-seq2)=0c;
  lim(seq1-seq2)=lim(seq1)-lim(seq2) by A1,COMSEQ_2:26;
  hence thesis by A2;
end;
