theorem
 for p being PartState of S holds Start-At(0,S) c= p implies IC p = 0
proof let p be PartState of S;
A1: IC Start-At(0,S) = 0 by Def11;
 IC S in dom Start-At(0,S) by Def11;
  hence thesis by A1,GRFUNC_1:2;
end;
