http://reply.papertrans.cn/3/296/29580/29580-31.png
http://reply.papertrans.cn/3/296/29580/29580-32.png
Submitted on: 29 May 2013.
Revised on: 13 June 2013.
Accepted on: 29 June 2013.
Tokyo Journal of Mathematics
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Submitted on: 30 July 2013.
Revised on: 13 August 2013.
Accepted on: 31 August 2013.
Tokyo Journal of Mathematics
http://reply.papertrans.cn/3/296/29580/29580-36.png