Xiaoqi Yang (杨晓琪)

Professor at Department of Applied Mathematics, Hong Kong Polytechnic University

Academic background

Professor Yang received his BSc degree in Mathematics from the Chongqing Jianzhu University, Chongqing, a MSc degree in Operations Research and Control Theory from the Institute of System Science at Chinese Academy of Science, China and a PhD degree in Applied Mathematics at University of New South Wales, Australia. He then spent five years at the School of Mathematics and Statistics in the University of Western Australia as a Research Associate (1994-1996), an Australian Research Council postdoctoral fellow (1997) and a lecturer (1998). Since 1999 he has been with the Department of Applied Mathematics, Hong Kong Polytechnic University, as an Assistant Professor (1999-2001), Associate Professor (2002-2004), Professor (2005- ). In 2000 he received the ISI Citation Classic for the paper "The vector complementary problem and its equivalences with the weak minimal element in ordered spaces", Journal of Mathematical Analysis and Applications, Vol. 153 (1990) pp. 136-158. In the same year he received the President's Award for Outstanding Performance / Achievement in the category of Research and Scholarly Activities, Hong Kong Polytechnic University. In 2006 he received The First Prize of Natural Science from the Chongqing Municipal Government in 2006.

I am looking for good graduate students who are interested in my research areas. You can contact me directly by email.

Research Monographs: 

Goh C.J. and Yang X.Q. Duality in Optimization and Variational Inequalities. CRC Press 2002

Rubinov A. and Yang X.Q. Lagrange-type Functions in Constrained Nonconvex Optimization. Kluwer 2003

Chen G.Y., Huang X.X. and Yang X.Q. Vector Optimization: Set-Valued and Variational Analysis. Springer 2005

Selected Publications:

Hu Y.H., Li C. and Yang X.Q., On convergence rates of linearized proximal algorithms for convex composite optimization with applications, (revised, 2015 Ocotber)

Hu Y.H., Li C., Qin J. and Yang X.Q. Group sparse optimization via l_{p,q} regularization  (revised May 2014, second revision 13 Dec 2015).

Meng K.W. and Yang X.Q. First- and second-order necessary conditions via exact penalty functions (submitted).

Tian B.S., Yang X.Q. and Meng K.W. An interior-point l0.5 penalty method for inequality constrained nonlinear optimization, (submitted).

Yang X.Q., Chen Z.Y. and Zhou J.C. Optimality conditions for semi-infinite and generalized semi-infinite programs via l_p exact penalty functions (submitted)


Meng, K.W. and Yang, X.Q. First- and second-order necessary conditions via exact penalty functions. J. Optim. Theory Appl. 165 (2015), no. 3, 720–752.

Fang, Y. P.; Meng, K. W.; Yang, X.Q. On minimal generators for semi-closed polyhedra. Optimization 64 (2015), no. 4, 761–770.

Meng, K.W., Roshchina, V. and Yang, X.Q. On local coincidence of a convex set and its tangent cone. J. Optim. Theory Appl. 164 (2015), no. 1, 123–137.

Chen, Z.Y.; Yang, X.Q. On global quadratic growth condition for min-max optimization problems with quadratic functions. Appl. Anal. 94 (2015), no. 1, 144–152.

Hu, Y.H.; Yang, X.Q; Sim, C.K. Inexact subgradient methods for quasi-convex optimization problems. European J. Oper. Res. 240 (2015), no. 2, 315–327.


Zhou, Y. Y.; Wang, S. and Yang, X.Q. A penalty approximation method for a semilinear parabolic double obstacle problem. J. Global Optim. 60 (2014), no. 3, 531–550.

Huang, X. X.; Fang, Y. P. and Yang, X.Q. Characterizing the nonemptiness and compactness of the solution set of a vector variational inequality by scalarization. J. Optim. Theory Appl. 162 (2014), no. 2, 548–558.

Zhou, Y. Y.; Zhou, J. C. and Yang, X.Q. Existence of augmented Lagrange multipliers for cone constrained optimization problems. J. Global Optim. 58 (2014), no. 2, 243–260.


Wang C.Y., Yang X.Q. and Yang X.M., Nonlinear augmented Lagrangian and duality theory, Mathematics of Operations Research 38 (2013), no. 4, 740–760.

Li, G.; Yang, X.Q. and Zhou, Y.Y. Stable strong and total parametrized dualities for DC optimization problems in locally convex spaces. J. Ind. Manag. Optim. 9 (2013), no. 3, 671–687.

Wang, G.; Yang, X. Q. and Cheng, T.C.E. Generalized Levitin-Polyak well-posedness for generalized semi-infinite programs. Numer. Funct. Anal. Optim. 34 (2013), no. 6, 695–711.


Fang Y.P., Meng K.W. and Yang X.Q., Piecewise linear multi-criteria programs: the continuous case and its discontinuous generalization. Operations Research  60 (2012), no. 2, 398-409.

Fang, Y.P., Huang, N.J. and Yang, X.Q. Local smooth representations of parametric semiclosed polyhedra with applications to sensitivity in piecewise linear programs. J. Optim. Theory Appl. 155 (2012), no. 3, 810–839.

Meng, K.W. and Yang, X.Q. Equivalent conditions for local error bounds. Set-Valued Var. Anal. 20 (2012), no. 4, 617–636.

Huang, N.J., Li, J. and Yang, X.Q. Weak sharpness for gap functions in vector variational inequalities. J. Math. Anal. Appl. 394 (2012), no. 2, 449–457.

Giannessi, F., Mastroeni, G. and Yang, X.Q. Survey on vector complementarity problems. J. Global Optim. 53 (2012), no. 1, 53–67.

Zheng, X.Y., Yang, X.Q. Conic positive definiteness and sharp minima of fractional orders in vector optimization problems. J. Math. Anal. Appl. 391 (2012), no. 2, 619–629.

Fang, D. H.; Li, C. and Yang, X.Q. Asymptotic closure condition and Fenchel duality for DC optimization problems in locally convex spaces. Nonlinear Anal. 75 (2012), no. 8, 3672–3681.

Huang, X.X. and Yang, X.Q. Further study on the Levitin-Polyak well-posedness of constrained convex vector optimization problems. Nonlinear Anal. 75 (2012), no. 3, 1341–1347.

Zhou, Y.Y. and Yang, X.Q. Augmented Lagrangian functions for constrained optimization problems. J. Global Optim. 52 (2012), no. 1, 95–108.

2011 and beyond

Fang D. H., Li, C. and Yang X. Q. Stable and total Fenchel duality for DC optimization problems in locally convex spaces. SIAM J. on Optimization. 21 (2011), no. 3, 730-760.

Meng K.W. and Yang X.Q., Optimality conditions via exact penalty functions SIAM J. on Optimization. Vol. 20, (2010) No. 6, pp. 3208-3231.

Yang X.Q. and Meng Z.Q., Lagrange multipliers and calmness conditions of order p, Mathematics of Operations Research Vol. 32 No. 1 (2007) pp. 95-101.

Wang S., Yang X.Q. and Teo K.L., A power penalty method for a linear complementarity problem arising from American option valuation, Journal of Optimization Theory and Applications Vol. 129, No. 2 (2006) pp. 227-254.

Deng S. and Yang X.Q., Weak sharp minima in multicriteria linear programming, SIAM J. on Optimization. Vol. 15, no. 2, (2004) pp. 456-460.

Huang X.X. and Yang X.Q., A unified augmented Lagrangian approach to duality and exact penalization. Mathematics of Operations Research. Vol. 28 (2003) pp. 524-532.

A List of References for Vector Variational Inequalities


2015/16: AMA2111 Engineering Mathematics; AMA532 Investment Science

2014/15: AMA2111 Engineering Mathematics; AMA532 Investment Science

Contact Information:

Telephone: (852) 2766 6954 
Fax: (852) 2362 9045 
E-mail: mayangxq at polyu.edu.hk

Office: TU706 
Department of Applied Mathematics, The Hong Kong Polytechnic University 
Kowloon, Hong Kong, China


Last updated on 1 September 2015