List of Publications

（Possibile Pen Name: Yi Ru-Ya Zhang）

The publications are listed according to the time when they were finished. 

1. Pekka Koskela, Jie Xiao, Yi Zhang and Yuan Zhou, A quasiconformal composition problem for the Q-spaces, J. Eur. Math. Soc., 19 (2017), no. 4, 1159–1187. http://arxiv.org/abs/1608.02009

2. Pekka Koskela, Yi Zhang and Yuan Zhou, Morrey-Sobolev extension domains, J. Geom. Anal. 27 (2017), no. 2, 1413–1434. 

3. Pekka Koskela, Tapio Rajala and Yi Zhang, A geometric characterization of planar Sobolev extension domains,  Sci. China Math. 68 (2025), no. 10, 2347–2416. 

4. Pekka Koskela and Yi Zhang, A density problem for Sobolev spaces on planar domains, Arch. Ration. Mech. Anal., 222 (2016), no. 1, 1–14. http://arxiv.org/abs/1508.01400

5. Pekka Koskela, Tapio Rajala and Yi Zhang, Planar $W^{1,\,1}$-extension domains, Preprint, https://jyx.jyu.fi/handle/123456789/53616 (the last paper) . 

6. Nicola Fusco, Yi Zhang, A quantitative form of the Faber-Krahn inequality, Calc. Var. Partial Differential Equations 56 (2017), no. 5, 56:138. http://cvgmt.sns.it/paper/3015/ 

7. Pekka Koskela, Tapio Rajala and Yi Zhang, A density problem for Sobolev spaces on Gromov hyperbolic domains, Nonlinear Anal. 154 (2017), 189–209. https://arxiv.org/abs/1605.08260

8. Herbert Koch, Yi Zhang, Yuan Zhou, An asymtotic sharp Sobolev regularity for planar infinity harmonic functions, J. Math. Pures Appl. (9) 132 (2019), 457–482. https://arxiv.org/abs/1806.01982

9. Herbert Koch, Yi Zhang, Yuan Zhou, Some sharp Sobolev regularity for inhomogeneous ∞-Laplace equation in plane, J. Math. Pures Appl. (9) 132 (2019), 483–521.  https://arxiv.org/abs/1806.01987

10. Nicola Fusco, Shirsho Mukherjee, Yi Zhang, A variational characterisation of the second eigenvalue of the p-Laplacian on quasi open sets, Proc. Lond. Math. Soc. (3) 119 (2019), no. 3, 579–612.  https://arxiv.org/abs/1806.07303

11. Yi Zhang, Schoenflies solutions of conformal boundary values may fail to be Sobolev, Ann. Acad. Sci. Fenn. Math. 44 (2019), no. 2, 791–796. https://arxiv.org/abs/1808.10392

12. Yi Zhang, Yuan Zhou, C^1-Regularity of planar \infty-harmonic functions - revisited, Proc. Amer. Math. Soc. 148 (2020), no. 3, 1187–1193. https://arxiv.org/abs/1905.06298

13. Hongjie Dong, Fa  Peng, Yi  Zhang, Yuan Zhou, Hessian estimates for equations involving p-Laplacian via a fundamental inequality, Adv. Math. 370 (2020), 107212, 40 pp.  https://arxiv.org/abs/1908.01547

14. Alessio Figalli, Yi Zhang, Strong stability for the Wulff inequality with a crystalline norm, Comm. Pure Appl. Math., 75 (2022), no. 2, 422–446. https://arxiv.org/abs/1910.09515 

15. Pekka Koskela, Pekka Pankka, Yi Zhang, Ahlfors reflection theorem for p-morphisms, Submitted. https://arxiv.org/abs/1912.09200 

16. Yi Zhang, Duality of capacities and Sobolev extendability in the plane, Complex Anal. Synerg. 7 (2021), no. 1, Paper No. 3, 6 pp. https://arxiv.org/abs/2002.01294

17. Alessio Figalli, Yi Zhang, Sharp gradient stability for the Sobolev inequality,  Duke Math. J. 171 (2022), no. 12, 2407–2459. https://arxiv.org/abs/2003.04037 

18. Fa Peng, Yi  Zhang, Yuan Zhou, Optimal regularity & Liouville property for stable solutions to semilinear elliptic equations in R^n with n\ge 10,  Anal. PDE 17 (2024), no. 9, 3335–3353. https://arxiv.org/abs/2105.02535

19. Alessio Figalli, Yi Zhang, Uniform boundedness for finite Morse index solutions to supercritica semilinear elliptic equations, Comm. Pure Appl. Math. 77 (2024), no. 1, 3–36.  https://arxiv.org/abs/2106.10959 

20. Fa Peng, Yi  Zhang, Yuan Zhou, Interior Holder regularity for stable solutions to semilinear elliptic equations up to dimension 5, Submitted. https://arxiv.org/abs/2204.06345 

21. Hongjie Dong, Fa Peng, Yi Zhang, Yuan Zhou, Jacobian determinants for (nonlinear) gradient of planar ∞-harmonic functions and applications,  J. Reine Angew. Math. 812 (2024), 59–98. . https://arxiv.org/abs/2209.02659 

22. Alessio Figalli, Yi Zhang, Strong stability of convexity with respect to the perimeter, Submitted. https://arxiv.org/abs/2307.01633 

23.  Fa Peng, Yi Zhang, Yuan Zhou, Regularity from p-harmonic potentials to \infty-harmonic potentials in convex rings, Proc. Lond. Math. Soc. (3) 130 (2025), no. 6, Paper No. e70062, 54 pp.

24. Weicong Su, Yi Zhang, Carrot John domains in variational problems, Ann. Fenn. Math. 50 (2025), no. 1, 157–185. https://arxiv.org/abs/2401.08133 

25. Weicong Su, Yi Zhang, John property of anisotropic minimal surfaces, Submitted. https://arxiv.org/abs/2406.06906 

26. Alessio Figalli, Yi Zhang, Serrin's overdetermined problem in rough domains, J. Eur. Math. Soc., to appear. https://arxiv.org/abs/2407.02293 

27. Yi Zhang, A growth estimate for the planar Mumford--Shah minimizers at a tip point: An alternative proof of David--L\'eger, Ann. Fenn. Math. 50 (2025), no. 1, 145–156.  https://arxiv.org/abs/2502.15605 

28. Gemei Liu, Yi Zhang, Sharp stability for critical points of the Sobolev inequality in the absence of bubbling, Submitted. https://arxiv.org/abs/2503.02340 

29. Hongjie Dong, Yi Zhang, Serrin's overdetermined theorem within Lipschitz domains, Submitted. https://arxiv.org/abs/2509.05155