Submitted on: 13 May 2007.
Revised on: 17 June 2007.
Accepted on: 09 July 2007.
Theory of Computing---UNIV CHICAGO, DEPT COMPUTER SCIENCE
Submitted on: 28 January 2009.
Revised on: 21 February 2009.
Accepted on: 11 March 2009.
Theory of Computing
http://reply.papertrans.cn/3/295/29429/29429-33.png
Submitted on: 16 October 2001.
Revised on: 11 November 2001.
Accepted on: 22 November 2001.
Theory of Computing---UNIV CHICAGO, DEPT COMPUTER SCIENCE
http://reply.papertrans.cn/3/295/29429/29429-35.png
Submitted on: 17 February 2006.
Revised on: 31 March 2006.
Accepted on: 24 April 2006.
Theory of Computing---UNIV CHICAGO, DEPT COMPUTER SCIENCE