http://reply.papertrans.cn/1/45/4487/4487-31.png
http://reply.papertrans.cn/1/45/4487/4487-32.png
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http://reply.papertrans.cn/1/45/4487/4487-34.png
Submitted on: 19 November 1999.
Revised on: 19 January 2000.
Accepted on: 11 February 2000.
___________________CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS
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