theorem Th36:
 for p being PartState of S, k,l being Nat
  holds p +* Start-At(k,S) +* Start-At(l,S)  = p +* Start-At(l,S)
proof let p be PartState of S, k,l be Nat;
  dom Start-At(k,S) = {IC S}
    .= dom Start-At(l,S);
 hence p +* Start-At(k,S) +* Start-At(l,S)  = p +* Start-At(l,S) by FUNCT_4:74;
end;
