Submitted on: 11 September 2001.
Revised on: 25 September 2001.
Accepted on: 21 October 2001.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 29 May 2006.
Revised on: 23 June 2006.
Accepted on: 18 July 2006.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 17 May 2018.
Revised on: 13 June 2018.
Accepted on: 26 June 2018.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 31 March 1998.
Revised on: 16 April 1998.
Accepted on: 08 May 1998.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 12 December 2020.
Revised on: 25 January 2021.
Accepted on: 04 February 2021.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 02 September 2007.
Revised on: 16 September 2007.
Accepted on: 07 October 2007.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 16 December 1999.
Revised on: 21 January 2000.
Accepted on: 17 February 2000.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
Submitted on: 01 June 2005.
Revised on: 25 June 2005.
Accepted on: 17 July 2005.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS
http://reply.papertrans.cn/3/254/25353/25353-29.png
Submitted on: 09 October 2002.
Revised on: 24 October 2002.
Accepted on: 19 November 2002.
PROCEEDINGS OF THE ROYAL SOCIETY OF EDINBURGH SECTION A-MATHEMATICS