theorem
  x in dom g implies <*f,g*>..(2,x) = g.x & <*f,g,h*>..(2,x) = g.x
proof
A1: 2 in Seg 2 & 2 in Seg 3 by Th1,ENUMSET1:def 1,FINSEQ_1:2,TARSKI:def 2;
A2: dom <*f,g*> = Seg 2 & dom <*f,g,h*> = Seg 3 by FINSEQ_1:89;
  <*f,g*>.2 = g & <*f,g,h*>.2 = g;
  hence thesis by A1,A2,FUNCT_5:38;
end;
