� Copyright (c) 1997, 2009, 2011 American Mathematical Society� ,,�� � ��^ x � � � � � Postscript Euler 4 � � ��� ��d 2 d � 2 2 2 V� o M �s kv`������3<�(Vk ��1W� �^*�� ll jj � 7 FEUSB10