reserve x,y,z for object,
  i,j,n,m for Nat,
  D for non empty set,
  s,t for FinSequence,
  a,a1,a2,b1,b2,d for Element of D,
  p, p1,p2,q,r for FinSequence of D;
reserve M,M1,M2 for Matrix of D;
reserve f for FinSequence of D;
reserve i,j,i1,j1 for Nat;
reserve k for Nat, G for Matrix of D;
reserve x,y,x1,x2,y1,y2 for object,
  i,j,k,l,n,m for Nat,
  D for non empty set,
  s,s2 for FinSequence,
  a,b,c,d for Element of D,
  q,r for FinSequence of D,
  a9,b9 for Element of D;

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;
