Jun Hu
Professor
Mathematics
Location: 1156 Ingersoll Hall
Phone: 718.951.5246
Fax: 718.951.4674
Email:
Jun Hu's Web site
Jun Hu joined the Brooklyn College Mathematics Department in 1999 and joined the Mathematics Doctoral Faculty at the Graduate Center in 2003. Hu chaired the BC Math Dept. in 2010-12 and Fall 2014-Fall 2017. Before joining BC, Hu was an assistant professor at Rutgers-Newark (1995-98) and an NSF postdoctoral fellow at the University of Maryland at College Park (fall 1998). In the academic year 2001-02, Hu was back on the NSF postdoctoral fellowship (visiting SUNY at Stony Brook) while taking an incentive scholar fellowship leave from CUNY. Hu was a visiting professor of mathematics at NYUShanghai in the spring semesters of 2018 and 2019 when he was on a fellowship leave from CUNY.
Education:
Ph.D., Graduate School & University Center (CUNY) - 1995 (Mathematics, General)
Areas of Expertise:
Chaos, bifurcations and fractal sets in low-dimensional dynamical systems, and dynamics of rational maps; conformally natural extensions of homeomorphisms of circle or sphere of any dimension; Thurston's earthquake theory on the hyperbolic plane; Teichmuller metric, Kobayashi metric, and length spectrum metric on Teichmuller spapces and asymptotical Teichmuller spaces; and real Teichmuller theory motivated by rigidity problems in smooth or conformal dynamical systems.
Books and Publications
"Characterizations of circle diffeomorphisms of different regularities in the universal Teichmuller space." Preprint, 26 pages, submitted. (Books and Publications: Forthcoming Publications) 2022
PSC-CUNY Research Award 53 - Type A, 2022-23 (Awards and Honors) 2022
Organizer of the Fudan-NYUShanghai-ECNU Conference on Ergodic Theory and Dynamical Systems on April 20 and 21. 2019
Co-organizer of the Conference on Four Decades of the Einstein Chair Seminar held at GC of CUNY, Jan. 17 - 19, 2023 (https://einstein-chair.github.io/fourdecades). 2023
Hu, Jun and Francisco G. Jimenez-Lopez. "Teichmuller spaces of nondiscrete groups." Annales Fennici Mathematici 47(1): 381-393 (Doi: 10.54330/afm.114460). (Books and Publications: Article (Peer-reviewed)) 2022
Jinhua Fan and Jun Hu. "Conformally natural extensions of vector fields and applications." Pure and Applied Math Quarterly 18(3), 1147-1186 (Doi: 10.4310/PAMQ.2022.v18.n3.a10). (Books and Publications: Article (Peer-reviewed)) 2022
Jinhua Fan, Jun Hu and Zhenyong Hu. "Douady-Earle extensions of circle homeomorphisms with one-point differentiability at a Holder convergence rate." Preprint, 12 pages, submitted .
(Books and Publications: Forthcoming Publications) 2022
Jun Hu and Arkady Etkin. "Cubic rational maps with escaping critical points, Part I: Julia set dichotomy in the case of an attracting fixed point." Qual. Theory of Dyn. Syst. 21:70 (Doi: 10.1007/s12346-022-00593-y). (Books and Publications: Article (Peer-reviewed)) 2022
Weiwei Cui and Jun Hu. "Totally ramified rational maps." Conformal Geometry and Dynamics, an Elec. Jour. of AMS, 26, 208-234 (doi.org/10.1090/ecgd/377). (Books and Publications: Article (Peer-reviewed)) 2022
"Generalized conformal barycentric extensions of circle maps." Handbook of Teichmuller Theory, Vol. VII. Ed. Athanase Papadopoulos. IRMA Lectures in Mathematics and Theoretical Physics Vol. 30 (European Mathematical Society), 215-238.
(Books and Publications: Book Chapter) 2020
Jun Hu and Arkady Etkin. "Julia sets of cubic rational maps with escaping critical points."
Arnold Mathematical Journal 6: 431-457 . (Books and Publications: Article (Peer-reviewed)) 2020
Hu, Jun and Oleg Muzician. "Cross-Ratio Distortion and Douady-Earle Extension: III. How to control the dilatation near the origin." Annals Academiae Scientarium Fennicae Mathematica 44: 523-536. (Books and Publications: Article (Peer-reviewed)) 2019
Hu, Jun and Xingqing Xiao. "No Herman rings for regularly ramified rational maps." Proceedings of American Mathematical Society 147(4): 1587-1596. . (Books and Publications: Article (Peer-reviewed)) 2019
Hu, Jun and Francisco G. Jimenez-Lopez. "Length spectrum characterization of asymptotic Teichmuller space."Monatshefte für Mathematik 186: 73-91 .
(Books and Publications: Article (Peer-reviewed)) 2018
Hu, Jun, Oleg Muzician and Xingqing Xiao. "Dynamics of regularly ramified rational maps: I. Julia sets of the maps in one-parameter families." Discrete and Continuous Dynamical Systems-Series A 38(7): 3189-3221. (Books and Publications: Article (Peer-reviewed)) 2018
Fan, Jinhua and Jun Hu. "A gluing theorem and applications in subspaces of the universal Teichmuller space." Contemporary Mathematics 696: 87-99. (Books and Publications: Article (Peer-reviewed)) 2017
Hu, Jun and Oleg Muzician. "Conformally Natural Extensions of Continuous Circle Maps: II. The General Case." Journal d'Analyse Mathématique 132.1:81-107. (Books and Publications: Article (Peer-reviewed)) 2017
Fan, Jinhua and Jun Hu. "Holomorphic contractibility and other properties of the Weil-Petersson and VMOA Teichmuller spaces." Annals Academiae Scientarium Fennicae Mathematica 41: 587-600. (Books and Publications: Article (Peer-reviewed)) 2016
Hu, Jun and Francisco G. Jimenez-Lopez. "Comparison Between the Teichmuller Distance and the Length Spectrum Distance Under Partial Twists." Annals Academiae Scientarium Fennicae Mathematica 41: 221-234. (Books and Publications: Article (Peer-reviewed)) 2016
Fan, Jinhua and Jun Hu. "Topological Characterization of an Asymptotic Teichmuller Space Through Measured Geodesic Laminations." Pure and Applied Mathematics Quarterly 11.3:403-449. (Books and Publications: Article (Peer-reviewed)) 2015
Chamanara, Reza, Jun Hu and Joel Zablow. "Extending the Dehn Quandle to Shears and Laminations on Torus." Fundamenta Mathematicae 225: 1-22. (Books and Publications: Article (Peer-reviewed)) 2014
Fan, Jinhua and Jun Hu. "Characterization of the Asymptotic Teichmuller Space of the Open Unit Disk Through Shears." Pure and Applied Mathematics Quarterly 10.3: 513-46. (Books and Publications: Article (Peer-reviewed)) 2014
Hu, Jun and Francisco G. Jimenez-Lopez. "Modified Length Spectrum Metric on Marked Teichmuller Spaces of Riemann Surfaces With Boundaries." Annals Academiae Scientarium Fennicae Mathematica 39: 513-26. (Books and Publications: Article (Peer-reviewed)) 2014
Hu, Jun and Susovan Pal. "Boundary Differentiability of Douady-Earle Extensions of Circle Diffeomorphisms." To appear in Pure and Applied Mathematics Quarterly. (Books and Publications: Article (Peer-reviewed)) 2013
"Earthquakes on the Hyperbolic Plane." Handbook of Teichmuller Theory, Vol. III. Ed.
Athanase Papadopoulos. IRMA Lectures in Mathematics and Theoretical Physics Vol. 17 (European Mathematical Society), 71-122. (Books and Publications: Book Chapter) 2012
Hu, Jun and Oleg Muzician. "Conformally Natural Extensions of Continuous Circle Maps: I. The Case When the Pushforward Measure Has No Atom." Contemporary Mathematics 575: 171-98. (Books and Publications: Article (Peer-reviewed)) 2012
Hu, Jun and Oleg Muzician. "Cross-Ratio Distortion and Douady-Earle Extension: I. A New Upper Bound on Quasiconformality." Journal of the London Mathematical Society 86.2: 387-406. (Books and Publications: Article (Peer-reviewed)) 2012
Hu, Jun and Oleg Muzician. "Cross-Ratio Distortion and Douady-Earle Extension: II. Quasiconformality and Asymptotic Conformality Are Local." Journal d'Analyse Mathématique 117.1: 249-71. (Books and Publications: Article (Peer-reviewed)) 2012
Hu, Jun, Francisco G. Jimenez and Oleg Muzician. "Rational Maps With Half Symmetries, Julia Sets, and Multibrot Sets in Parameter Planes." Contemporary Mathematics 573: 119-46. (Books and Publications: Article (Peer-reviewed)) 2012
Hu, Jun and Zhe Wang. "Remarks on Chirka's Proof of Slodkowski's Theorem." Advances in Mathematics (China) 40.3: 325-38. (Books and Publications: Article (Peer-reviewed)) 2011
Hu, Jun, Yunping Jiang and Zhe Wang. "Kobayashi's and Teichmuller's Metrics on the Teichmuller Space of Symmetric Circle Homeomorphisms." Acta Mathematica Sinica, English Series 27.3: 617-24. (Books and Publications: Article (Peer-reviewed)) 2011
Gardiner, F.P. and Jun Hu. "A Short Course on Teichmuller's Theorem." Teichmuller Theory and Moduli Problems. Ramanujan Mathematical Society Lecture Notes Series 10: 195-228. (Books and Publications: Article (Peer-reviewed)) 2010
Gardiner, F.P. and Jun Hu. "Finite Earthquakes and the Associahedron." Teichmuller Theory and Moduli Problems. Ramanujan Mathematical Society Lecture Notes Series 10: 179-94. (Books and Publications: Article (Peer-reviewed)) 2010
"From Left Earthquakes to Right." Contemporary Mathematics 432: 75-92. (Books and Publications: Article (Peer-reviewed)) 2007
Hu, J. and M. Su. "Thurston Unbounded Earthquake Maps." Annals Academiae Scientarium Fennicae Mathematica 32: 125-39. (Books and Publications: Article (Peer-reviewed)) 2007
"Norms on Earthquake Measures and Zygmund Functions." Proceedings of the AMS 133: 193-202. (Books and Publications: Article (Peer-reviewed)) 2005
Gardiner, F.P. and Jun Hu. "An Earthquake Version of the Jackson-Zygmund Theorem." Annals Academiae Scientarium Fennicae Mathematica 30: 237-60. (Books and Publications: Article (Peer-reviewed)) 2005
"Continuous Extensions Are Not Holder." International Journal of Bifurcation and Chaos 14.4: 1501-05. (Books and Publications: Article (Peer-reviewed)) 2004
"Earthquake Measure and Cross-Ratio Distortion." Contemporary Mathematics 355: 285-308. (Books and Publications: Article (Peer-reviewed)) 2004
"On a Norm of Tangent Vectors to Earthquake Curves." Advances in Mathematics (China) 33.4: 401-14. (Books and Publications: Article (Peer-reviewed)) 2004
"Feigenbaum quadratic map: External rays and non-Holder continuity." Complex Dynamics and Related topics, Ed. Y. Jiang and Y. Wang. New Studies in Advanced Mathematics Vol. 5 (International Press, Somerville, MA), 218-235. (Books and Publications: Article (Peer-reviewed)) 2003
"Thurston's earthquake measures of Sullivan's circle diffeomorphisms." Complex Dynamics and Related topics, Ed. Y. Jiang and Y. Wang. New Studies in Advanced Mathematics Vol. 5 (International Press, Somerville, MA), 198-217. (Books and Publications: Article (Peer-reviewed)) 2003
Gardiner, F.P., Jun Hu and Niklai Lakic. "Earthquake curves." Contemporary Mathematics 311:141-195.
(Books and Publications: Article (Peer-reviewed)) 2002
Hu, Jun and Yunping Jiang. "The Julia set of the Feigenbaum quadratic polynomial." Dynamical Systems - Proceedings of the International Conference on Dynamical Systems in Honor of Professor Shantao Liao (Beijing, August 1998), Ed. Yunping Jiang and Wen Lan. World Scientific, 99-124. (Books and Publications: Article (Peer-reviewed)) 1999
"Bounded geometry in the supports of ergodic invariant probability measures." International Journal of Bifurcation and Chaos. 8.10:1957-1973. (Books and Publications: Article (Peer-reviewed)) 1998
"Feigenbaum's rigidities and dynamical systems between simple and chaotic."Advances in Mathematics (China) 27.5: 385-402. (Books and Publications: Article (Peer-reviewed)) 1998
Hu, Jun and Charles Tresser. "Period doubling, entropy, and renormalization." Fundamenta Mathematicae} 155(3): 237-249. (Books and Publications: Article (Peer-reviewed)) 1998
Hu, Jun and Dennis P. Sullivan. "Topological conjugacy of circle diffeomorphisms." Ergodic
Theory and Dynamical Systems 17:173-186. (Books and Publications: Article (Peer-reviewed)) 1997
Atela, Pau and Jun Hu. "Commuting polynomials and polynomials with same Julia sets." International Journal of Bifurcation and Chaos 6.12A: 2427-2432. (Books and Publications: Article (Peer-reviewed)) 1996
Awards, Honors and Fellowships
PSC-CUNY Research Award 51 - Type A, 2020-21 (Grants and Fellowships) 2020
PSC-CUNY Research Award 50 - Type A, 2019-20. (Grants and Fellowships) 2019
PSC-CUNY Research Award 48 - Type A, 2017-18. (Grants and Fellowships) 2017
PSC-CUNY Research Award 46 - Type A, 2015-16. (Grants and Fellowships) 2015
PSC-CUNY Research Award 44 - Type B, 2013-14. (Grants and Fellowships) 2013
Support of three-hour reassigned time from the Office of the Provost. (Awards and Honors) 2013
PSC-CUNY Research Award 43 - Type A, 2012-13. (Grants and Fellowships) 2012
PSC-CUNY Research Award 41, 2010-11. (Grants and Fellowships) 2011
CUNY Central Office of Academic Affairs Grant, for "Improving Undergraduate Mathematics Learning," Sandra Kingan (principal investigator) and Jun Hu and Anthony E. Clement (co-principal investigators), 2010-12. (Grants and Fellowships) 2010
PSC-CUNY Research Award 40, 2009-10. (Grants and Fellowships) 2010
PSC-CUNY Research Award 39, 2008-09. (Grants and Fellowships) 2009
PSC-CUNY Research Award 38, 2007-08. (Grants and Fellowships) 2008
PSC-CUNY Research Award 37, 2006-07. (Grants and Fellowships) 2007
PSC-CUNY Research Award 36, 2005-06. (Grants and Fellowships) 2006
PSC-CUNY Research Award 35, 2004-05. (Grants and Fellowships) 2005
CUNY Collaborative Research Grant. Jun Hu and Yunping Jiang, co-principal investigators. 2004-08. (Grants and Fellowships) 2004
PSC-CUNY Research Award 34, 2003-04. (Grants and Fellowships) 2004
PSC-CUNY Research Award 33, 2002-03. (Grants and Fellowships) 2003
PSC-CUNY Research Award 32, 2001-02. (Grants and Fellowships) 2002
PSC-CUNY Research Award 31, 2000-01. (Grants and Fellowships) 2001
PSC-CUNY Research Award 30, 1999-2000. (Grants and Fellowships) 2000
NSF Postdoctoral Research Fellowship, 1998-2002. (Grants and Fellowships) 1998
Research Activities
Visiting Professor of Mathematics at NYUShanghai. Spring semester. 2019
Organizer of the Fudan-NYUShanghai Joint Seminar on Low-dimensional Dynamical Systems and Teichmuller spaces. Spring semester. 2018
Visiting Professor of Mathematics at NYUShanghai. Spring semester. 2018
Hu, Jun and Saeed Zakeri, organizers, Complex Analysis and Dynamics Seminar, CUNY Graduate Center, fall 2005-present. http://qcpages.qc.cuny.edu/~zakeri/seminar.html. 2015
Hu, Jun, Reza Chamanara and Nik Lakic, co-organizers, two-day international conference in Teichmuller theory and related topics. Supported by the Mathematics departments of Brooklyn College and the CUNY Graduate Center. CUNY Graduate Center. New York, March 20-21. http://usehome.brooklyn.edu/rchamanara/Fred. 2009
Other Professional Activities
Co-organizer, Conference on Conformal Dynamics and Hyperbolic Geometry, which celebrates the contributions of Linda Keen. Supported by NSF, CUNY Graduate Center and Lehman College (CUNY). CUNY Graduate Center, Oct. 21-23. http://userhome.brooklyn.cuny.edu/rchamanara/Linda/index.htm. 2010
Co-organizer, Student Learning Seminar in Complex Analysis, CUNY Graduate Center, Fall. 2007
