reserve a,b,p,k,l,m,n,s,h,i,j,t,i1,i2 for natural Number;

theorem Th25:
  n mod n = 0
proof
  per cases;
  suppose
A1: n>0;
    n=n*1+0;
    hence thesis by A1,Def2;
  end;
  suppose n = 0;
    hence thesis by Def2;
  end;
end;
