theorem Th44:
  Segm(A,{i0},{j0}) = <*<* A*(i0,j0) *>*>
proof
A1: card {j0}=1 by CARD_1:30;
A2: Sgm {i0}=<*i0*> by FINSEQ_3:44;
A3: <*j0*>.1=j0;
A4: <*i0*>.1=i0;
A5: Sgm {j0}=<*j0*> by FINSEQ_3:44;
  card {i0}= 1 by CARD_1:30;
  hence thesis by A1,A2,A5,A4,A3,Th21;
end;
