# Ye-Kai Wang (王業凱)

Associate Professor of Mathematics
[Department of Applied Mathematics, National Yang Ming Chiao Tung University](https://www.math.nycu.edu.tw/event/index.php), Hsinchu, Taiwan
Email: yekaiwang at nycu.edu.tw

## Education
Ph.D. Mathematics, Columbia University 2014. Advisor: Professor [Mu-Tao Wang](https://http://www.math.columbia.edu/~mtwang/)
M.S. Mathematics, National Taiwan University 2008. Advisor: Professor [Yng-Ing Lee](https://www.math.ntu.edu.tw/entity_people/entity_people/21459)

## Publication
My research interest lies in [mathematical general relativity](https://arxiv.org/abs/1004.1016).
1. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Supertranslation invariance of angular momentum at null infinity in double null gauge](https://arxiv.org/abs/2204.03182) Pure Appl. Math. Q. 20 (2024), no. 4, 1635–1666.
2. B. Harvie; Y.-K. Wang [A rigidity theorem for asymptotically flat static manifolds and its applications.](https://arxiv.org/abs/2305.08570) Trans. Amer. Math. Soc. 377 (2024), no. 5, 3599–3629.
3. P.-N. Chen; D. Paraizo; R. Wald; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Cross-section continuity of definitions of angular momentum.](https://arxiv.org/abs/2207.04590) Classical Quantum Gravity 40 (2023), no. 2, Paper No. 025007, 11 pp.
4. B. Harvie, Y.-K. Wang [The mass of the static extension of small spheres.](https://arxiv.org/abs/2209.00141) Int. Math. Res. Not. IMRN(2024), no. 2, 1606–1623.
5. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau. [BMS charges without supertranslation ambiguity.](https://arxiv.org/abs/2107.05316) Comm. Math. Phys. 393 (2022), no. 3, 1411–1449.
6. B.-H. Wang; Y.-K. Wang [A note on the convex body isoperimetric conjecture in the plane.](https://arxiv.org/abs/2104.04954) Proc. Amer. Math. Soc. 152 (2024), no. 2, 801–813.
7. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Quasi-local mass on unit spheres at spatial infinity.](https://arxiv.org/abs/1901.06954) Comm. Anal. Geom. 30 (2022), no. 4, 745–777.
8. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Supertranslation invariance of angular momentum.](https://arxiv.org/abs/2102.03235) Adv. Theor. Math. Phys. 25 (2021), no. 3, 777–789.
9. P.-N. Chen; J. Keller; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Evolution of angular momentum and center of mass at null infinity.](https://arxiv.org/abs/2102.03221) Comm. Math. Phys. 386 (2021), no. 1, 551–588.
10. J. Keller; Y.-K. Wang; S.-T. Yau [Evaluating Quasi-local Angular Momentum and Center-of-Mass at Null Infinity](https://arxiv.org/abs/1811.02383) Adv. Theor. Math. Phys. 24 (2020), no. 6, 1423–1473.
11. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Quasi-local mass at null infinity in Bondi-Sachs coordinates.](https://arxiv.org/abs/1901.06952) Pure Appl. Math. Q. 15 (2019), no. 3, 875–895.
12. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Quasi-local mass at axially symmetric null infinity.](https://arxiv.org/abs/1901.06948) Internat. J. Modern Phys. D 28 (2019), no. 8, 1930013, 7 pp.
13. P.-N. Chen; M.-T. Wang; Y.-K. Wang; S.-T. Yau [Quasi-local energy with respect to a static spacetime.](https://arxiv.org/abs/1604.02983) Adv. Theor. Math. Phys. 22 (2018), no. 1, 1–23.
14. X. Wang; Y.-K. Wang [Brendle's inequality on static manifolds.](https://arxiv.org/abs/1603.00379) J. Geom. Anal. 28 (2018), no. 1, 152–169.
15. M.-T. Wang; Y.-K. Wang; X. Zhang [Minkowski formulae and Alexandrov theorems in spacetime.](https://arxiv.org/abs/1409.2190) J. Differential Geom. 105 (2017), no. 2, 249–290.
16. P.-N. Chen; M.-T. Wang; Y.-K. Wang [Rigidity of time-flat surfaces in the Minkowski spacetime.](https://arxiv.org/abs/1310.6081) Math. Res. Lett. 21 (2014), no. 6, 1227–1240.
17. C.-Y. Lin; Y.-K. Wang [On isometric embeddings into anti-de Sitter spacetimes.](https://arxiv.org/abs/1401.6026) Int. Math. Res. Not. IMRN 2015, no. 16, 7130–7161.

## Teaching
The courses I taught other than Calculus:
1. Fall 2021: Introduction to Probability, Introduction to Differential Geometry
2. Fall 2020: Complex Analysis (based on Gamelin's book)
3. Fall 2019: Geometry II (minimal surface based on Oprea's book)
4. Spring 2019: Introduction to Differential Geometry II
5. Fall 2017: Introduction to Differential Geometry (manifolds)
6. Spring 2017: Geometry (curves and surfaces)

## Activities
[2020 NCTS 寒假短期課程 Curve shortening flow](https://jupiter.math.nycu.edu.tw/~ykwang/CSF_Winter_School.html)

[紀錄片放映 Secrets of The Surface (The Mathematical Vision of Maryam Mirzakhani)](https://jupiter.math.nycu.edu.tw/~ykwang/Mirz.html)

[(成大數學)幾何組修課建議](https://jupiter.math.nycu.edu.tw/~ykwang/NCKU_Geometry.html)

[Articles about Geometric Analysis or Mathematical General Relativity](https://jupiter.math.nycu.edu.tw/~ykwang/articles.html)