The Infinite-Dimensional Widths and Optimal Recovery of Generalized Besov Classes. - Yongping Liu; Guiqiao Xu (J. Complex., 2002)

The Simultaneous Approximation of Quasi-Hermite Interpolation on the Weighted Mean Norm. - Guiqiao Xu; Ran Cui; Xin Wang (Int. J. Wavelets Multiresolution Inf. Process., 2009)

The relative n-widths of Sobolev classes with restrictions. - Guiqiao Xu (J. Approx. Theory, 2009)

Average errors for Kantorovitch operators on r-fold integrated Wiener space. - Guiqiao Xu; Xingrui Gao (Int. J. Wavelets Multiresolution Inf. Process., 2014)

Quasi-polynomial tractability of linear problems in the average case setting. - Guiqiao Xu (J. Complex., 2014)

Tractability of linear problems defined over Hilbert spaces. - Guiqiao Xu (J. Complex., 2014)

On weak tractability of the Smolyak algorithm for approximation problems. - Guiqiao Xu (J. Approx. Theory, 2015)

Exponential convergence-tractability of general linear problems in the average case setting. - Guiqiao Xu (J. Complex., 2015)

The best constants in the Wirtinger inequality. - Yongping Liu; Wenyan Wu 003; Guiqiao Xu (Int. J. Wavelets Multiresolution Inf. Process., 2016)

A note on tractability of multivariate analytic problems. - Yongping Liu; Guiqiao Xu (J. Complex., 2016)

Average case tractability of a multivariate approximation problem. - Yongping Liu; Guiqiao Xu (J. Complex., 2017)

EC-(s, t)-weak tractability of multivariate linear problems in the average case setting. - Anargyros Papageorgiou; Iasonas Petras; Guiqiao Xu; Dong Yanqi (J. Complex., 2019)

Simultaneous approximation of Birkhoff interpolation and the associated sharp inequalities. - Zehong Liu; Wanting Lu; Guiqiao Xu (Int. J. Wavelets Multiresolution Inf. Process., 2020)

EC-tractability of Lp-approximation in Korobov spaces with exponential weights. - Guiqiao Xu (J. Approx. Theory, 2020)

On the power of standard information for L2-approximation in the average case setting. - Guiqiao Xu (J. Complex., 2020)

Average case tractability of non-homogeneous tensor product problems with the absolute error criterion. - Guiqiao Xu (J. Complex., 2023)

A kind of sharp Wirtinger inequalities. - Guiqiao Xu; Yongping Liu; Dandan Guo (Int. J. Wavelets Multiresolution Inf. Process., 2024)

Gaussian quadrature formulae are strongly asymptotically optimal for a class of infinitely differentiable functions. - Guiqiao Xu (J. Approx. Theory, 2025)