Submitted on: 27 May 2019.
Revised on: 20 August 2019.
Accepted on: 10 September 2019.
___________________Involve, a journal of mathematics
Submitted on: 12 July 1998.
Revised on: 07 August 1998.
Accepted on: 26 August 1998.
___________________Involve, a journal of mathematics
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http://reply.papertrans.cn/2/146/14542/14542-14.png
Submitted on: 04 July 2012.
Revised on: 23 September 2012.
Accepted on: 18 October 2012.
___________________Involve, a journal of mathematics
http://reply.papertrans.cn/2/146/14542/14542-16.png
http://reply.papertrans.cn/2/146/14542/14542-17.png
http://reply.papertrans.cn/2/146/14542/14542-18.png
Submitted on: 16 June 2014.
Revised on: 20 August 2014.
Accepted on: 18 October 2014.
___________________Involve, a journal of mathematics
Submitted on: 19 May 2003.
Revised on: 08 September 2003.
Accepted on: 28 September 2003.
___________________Involve, a journal of mathematics