Service
- Series Editor for ``Monographs in Number Theory'' published by World Scientific Publishing Company (2008-2012)
- Editor for ``The Ramanujan Journal'' published by Springer Verlag. (2002-2011)
- Editor for `` International Journal of Number Theory'' published by the World Scientific Publishing Company. (2005-2012)
- Reviewer for Zentralblatt Math published by Springer Verlag. (1999-2013)
- Reviewer for Mathematical Reviews published by American Math. Soc.. (1997-2012)
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Referees for various journals beginning 1995. These journals include
- Acta Arithmetica
- Adv. in Math.
- Amer. Math. Monthly
- Bull. of Lond. Math. Soc.
- Canadian Math. Bull.
- Comptes Rendus Math
- Discrete Math
- Glasgow Math. J.
- International J. of Number Theory
- J. Comb. Theory (Ser. A)
- J. Lond. Math. Soc.
- J. Math. Analysis and Applications
- J. Number Theory
- Math. Zeitschritft,
- Monatshefte in Math.
- Proc. Lond. Math. Soc.
- The Ramanujan J
- Trans. Amer. Math. Soc.
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Service at National University of Singapore:
- Academic advisor for Arts and Social Sciences Students majoring in mathematics (1997-2003)
- Strategic Planning Committee (member, 2000-2003)
- Curriculum Committee (member, 2001–2005) (member, 2007)
- Department Teaching Evaluation Committee (member, 2008--).
- Academic advisors committee (member, in charge of second and third year modules) (2006–-)
- Elected Member of Department Executive committee (AY 2008/2009)
- Member of the Discretionary Admission interview board (2003,2006,2010,2011)
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Service (Ministry of Education)
- Judge for Singapore Science and Engineering Fair (2006, 2010, 2011, 2014)
- Supervisor for Science Research Programme (1997, 2003, 2005, 2007)
- Member of the Accreditation Committee for the NUS high school (Mathematics) (2006-2008).
- Member of Interview Board to select PRC scholars (2003, 2004, 2007, 2011).