theorem
  [1,1] in Indices <*<*a*>*> & <*<*a*>*>*(1,1)=a
proof
  set M=<*<*a*>*>;
  Indices M= [:Seg 1,Seg 1:] & 1 in Seg 1 by Th24,FINSEQ_1:2,TARSKI:def 1;
  hence
A1: [1,1] in Indices <*<*a*>*> by ZFMISC_1:87;
  M.1= <*a*> & <*a*>.1=a;
  hence thesis by A1,Def5;
end;
