September 18-22, "Geometry beyond Riemann: Curvature and Rigidity", Erwin Schroedinger Institute in Vienna, Austria

July 17-19 2023, " Characters and Moduli of Surfaces , Kyoto Math Institute, Kyoto, Japan

** July 31-August 6, ICCM, Beijing, China
**

** June 20-24, ****
"Spherical surfaces and related topics", cortona, Italy
**

** August 19-22, Computational and Applied Mathematics-ICCM, Nanjing, China. (deferred)
**

** July 26-30, Computational & Algorithmic Topology, Sydney, Australia.
**

** Apil 30, colloquium, New Mexico State University.
**

** April 28, colloquium, Rutgers at Newark.
**

** March 22, International Academic Symposium
"Mathematical Science of Visualization, and Deepening of Symmetry and Moduli", Osaka, Japan
**

** August, 10-14, Banff workshop, Banff, Canada (cancelled)
**

** July 27-31, Computational & Algorithmic Topology, Sydney, Australia. (deferred)
**

** July 6-10,
circle packing and geometric rigidity, ICERM, Brown University, Providence.
**

** June 14-19, Spherical surfaces and related topics , Cortona, Italy (deferred)
**

** June 8-10, Characters and Moduli of Surfaces, Nara, Japan (cancelled)
**

** March 4-9, International Academic Symposium
"Mathematical Science of Visualization, and Deepening of Symmetry and Moduli", Osaka, Japan. (deferred)
**

** Jan. 6-9, Frontier of Analysis and Geometry of Teichmuller Spaces, Sanya conference, China
**

** Oct. 21-23, ATD workshop, George Washington University, DC.
**

** Sept, 20-22, workshop on discrete shapes, UC Davis
**

** April 24, Colluquium speaker, UC San Diego
**

** Feb. 27, seminar talk at Brown University
**

** Feb. 13, seminar talk at Harvard
**

** Jan. 22, seminar talk at UC Santa Barbara
**

** Oct. 8-12, 2018, Invited speaker,
Discretization in Geometry and Dynamics, Döllnsee-Schorfheide, Templin, Germany. My talk discrete conformal geometry of polyhedral surfaces.
**

** July 9-13, co-organizer,
Geometry, Quantum Topology and Asymptotics 2018, conference at the Sandbjerg Estate, Denmark.
**

** July 2-6, co-organizer, summer school on
Geometry, Quantum Topology and Asymptotics 2018, Confucius Institute, University of Geneva, Switzerland.
**

** April 20, PATCH Seminar, Philadelphia.
**

**
**

** 2017
**

** Oct. 9-13, Geometric analysis,
organized by Centre Henri Lebesgue, University of Brest and University of Nantes, at Station Biologique de Roscoff, France. My talk discrete conformal geometry of polyhedral surfaces.
**

** Oct. 7, Workshop on Topology: Identifying Order in Complex Systems. University of Pennsylvania, Pennsylvania.
**

** Sept. 14-15, ATD workshop, American University, DC.
**

** July 10-19, Computational Topology and Geometry, FoCM'17, Barcelona, Spain.
**

** June 12-16, Geometry and Shape Analysis in Biological Sciences, National University of Singapore, Singapore.
**

** May 16, seminar talk at Station Q, Microsoft, Santa Barbara, California.
**

** May 11, topology seminar, UC Davis, Davis, California
**

** March 13-17, Curvatures of graphs, simplicial complexes and metric spaces, Sanya International Mathematics Forum, Sanya, China.
**

** 2016
**

** Dec. 12-17, 2016, Quantum invariants and low-dimensional topology, The international Mathematical Research Institute MATRIX, Victoria, Australia
**

** Sept 24-25, Eastern AMS Sectional meeting, Bowdoin College in Brunswick, Maine.
**

** August 15-19, 2016, "Program on Geometry, Topology and Dynamics of Moduli Spaces", National University of Singapore, Singapore.
**

** August 13-14, 2016, “Workshop on Discrete Analysis”,
Shanghai Center of Mathematical Sciences, Fudan University, Shanghai, China.
**

** July 24-30, 2016, "On the Grothendieck-Teichmüller theory and mapping class groups", Chern Institute of Mathematics, Tianjin, China
**

** June 27-July 1, 2016,
Geometric Analysis, Metric Geometry and Topology at Institut Fourier, Grenoble, France.
**

** June 20-June 24, 2016, give a lecture series titled "An introduction to discrete conformal geometry of polyhedral surfaces" in the summer school
Geometric analysis, Metric geometry and Topology, Institut Fourier, Grenoble, France.
Videos:
Lecture 1 ,
Lecture 2 ,
Lecture 3 ,
Lecture 4 ,
Lecture 5
**

** May 3-19, 2016, University of Sydney, Australia
**

** March 19-20, AMS regional meeting at Stony Brook
**

**
Jan. 11-16, “Teichmüller theory and low-dimensional topology” , Sanya International Mathematics Forum, Sanya, China
**

** 2015
**

** Oct. 5-9, 2015, "Geometric Structures on 3-Manifolds", IAS, Princeton, NJ. My talk Rigidity of the hexagonal triangulation of the plane and its applications.
**

** August 10-14, 2015, organizer,
Invariants in low dimensional geometry, Gazi University, Ankara, Turkey.
**

** August 2-8, 2015, visiting and giving a talk at CENTRE FOR QUANTUM GEOMETRY OF MODULI SPACES, Aarhus, Denmark.
**

** July 6-10, 2015, Scientific committee,
Classical and quantum hyperbolic geometry and topology, Université Paris-Sud (Orsay), France.
**

** April 21-22, 2015, Identities in New York , CUNY graduate center. New York.
**

** April 16, 2015, topology seminar, Princeton Univ.
**

** April 14, 2015, colloquium speaker, Purdue University
**

** March 26, 2015, topology seminar, Stony Brook
**

** March 1-7, 2015, Oberwolfach workshop on discrete differential geometry, Germany
**

** Jan. 15, 2015, topology seminar, Caltech
**

** Jan. 13, 2015, Microft Station Q seminar, Santa Barbara
**

** 2014
**

** Dec. 15-19, Sanya International Mathematics Forum, Sanya, China
**

** August 22-26,
Knots and Low Dimensional Manifolds , Busan, Korea.
**

** August 4-8,
geometry and physics of Higgs bundles, National University of Singapore, Singapore
**

** July 27-Aug. 1, Mathematical Foundation of Modern Data Sciences, Dalian, China
**

** June 30-July 5, co-organizer, Geometry, Quantum Topology and Asymptotics, University of Geneva, Switzerland
**

** Mar 15-22, University of Sydney and University of Melbourn, Australia
**

** Mar 10-12, ATD workshop, Boulder, Colorado.
**

** Feb. 9-15, Oberwolfach workshop on Teichmuller theory and mapping class groups, Germany
**

**
**

** 2013
**

** Nov. 5-8, "Geometry of Moduli Spaces of Low Dimensional Manifolds", RIMS, Kyoto University, Japan
**

** Oct. 23, colloquium talk, Lehigh University
**

** Oct. 12, special session of AMS meeting, Philadelphia
**

** Sept. 11-15, BMS/SFB Summer School: Discrete Differential Geometry, Berlin, Germany
**

** August 12-16,
Geometric Topology in New York, Columbia University
**

** July 14-19, ICCM 2013, Taiwan
**

** May 8-June 14, visiting and giving a lecture series at
Mathematical Sciences Center (MSC)
, Tsinghua University, Beijing China
**

** April 26-28, Workshop on Minimal Surfaces, 3-Manifold Topology and Related Topics, MIT
**

** April 18, colloquium talk, SUNY, Stony Brook
**

** April 7-12, Banff workshop, Canada
**

** March 16-24, University of Pisa, Italy
**

**
2012
**

**
**

**
August 3-6, invited speaker, "International conference on complex geometry, singularities and related fields",
Beijing, China.
**

**
July 21-29, invited speaker, "International conference on group actions and applications in geometry,
topology and analysis", Kunming, China.
**

**
July 19-21, invited speaker,
The 3-D Geometry/Imaging Conference, Kunming, China.
**

**
July 8-14, invited speaker, Oberwolfach workshop on Discrete Differential Geometry, Germany
**

**
June 25-29, invited speaker, Mapping
Class Groups and Quantum Topology, IRMA, University of Strassboug, France
**

**
April 29-May 5, invited speaker, Oberwolfach workshop on Triangulations, Germany
**

**
March 26-April 25, invited lecturer,
Mathematical Science Center, Tsinghua University,
Beijing, China
**

**
April 13, colloquium talk, School of Math, Peking University, Beijing China
**

**
**

**
March 22, Topology seminar, SUNY Stony Brook
**

**
2011
**

**
March 13-14, invited speaker,
geometry and topology workshop, Princeton University.
**

**
May 25-26, invited speaker,
"Knots and Applications", Centro di Ricerca Matematica Ennio De Giorgi, Pisa, Italy.
My talk
"a dilogarithm identity on moduli spaces of curves".
**

** June 14-July 16, a series of 20-hour-lectures on Riemann surfaces and Teichmuller theory,
Mathematical Science Center, Tsinghua University,
Beijing, China,
**

** July 8, seminar speaker at the dept of Math, The Capital Normal University, Beijing, China.
**

** July 14, seminar speaker at the Mathematics Institute of the Chinese Acadmey of Science, Beijing, China.
**

**
July 18-22,
invited speaker,
"Geometry & Topology Down Under" (Hyamfest), The University of Melbourne, Australia,
My talk
"variational principles and rigidity on triangulated surfaces".
**

** Oct. 6, Topology seminar at Princeton University
**

** Oct. 21, Topolog seminar at Columbia University
**

** Nov. 15, Topology seminar at Temple University
**

** Dec. 13, Geometry seminar at UC San Diego
**

**
2010
**

**
Jan. 8, topology seminar, Caltech, Los Angeles
**

**
Jan. 12, topology seminar, UC Santa Barbara
**

** April 15, Topology seminar, City University of New York, Graudate Center
**

**
May 17-21, invited speaker,
Barrett Memorial Lectures, University of Tennessee, Knoxville
my lecture.
**

**
June 4-6, speaker and co-organizer,
"Topology and geometry in dimension
three"- celebrating Jaco's 70-th birthday, University of Oklahoma, Stillwater
**

**
July 7-16, invited speaker, workshop on geometric topology, Changchun, China.
**

**
**

** July 16, invited lecture at the Center of Mathematical Science, Qinghua University, Beijing
**

** July 19, invited lecture at the Beijing International Center for Mathematical Research, Beijing
**

** July 20, invited lecture at the capital Normal University, Beijing
**

**
July 19-30, invited speaker,
Topology, Geometry and Dynamics of character varieties,
National University of Singapore
**

** August 11-12, invited speaker, Sullivan Seminar, State University of New York, NY
**

**
Sept. 2-4, invited speaker,
Encounters between
mathematicians and theoretical physicists, University of Strassboug, France
**

**
Dec. 17-20, invited speaker, International Congress of Chinese Mathematicians, Qinghua University,
China.
**

**
2009
**

** Jan. 5-6, invited speaker, AMS meeting at Washington DC.
**

** Jan. 10-17, invited speaker, Oberwolfach workshop on discrete differential geometry
**

** Feb. 11-15, colloquium talk at Arizona State
**

** April 14, seminar talk at University of Maryland
**

** June 15-19, invited speaker, "Interactions Between Hyperbolic Geometry, Quantum Topology and Number Theory ", Columbia University, New York
**

** July 7-14, invited speaker, "Workshop on low-dimensional manifolds", East China Normal University, Shanghai, China
**

**
2008
**

** March 13, 2008, invited speaker, topology seminar, Princeton University
**

**
April 25, 2008, colloquium speaker, Okalahoma State University.
**

**
May 13, 2008, invited speaker, bay area topology seminar,
Univ. of California, Davis.
**

** June 4, 2008, invited speaker,
Mini-Symposia, IEEE International Conference on Shape Modeling and Applications
, State University of New York, Stony Brook.
**

**
June 16-28, 2008, invited speaker,
International workshop and conference on surface mapping class groups and related topics. Meghalaya, India.
**

** June 30-July 11, 2008,
Invited speaker,
Transformation groups and orbifolds. Hangzhou, China
**

** July 14-20, 2008,
Invited speaker,
Geometry of Teichmuller spaces and moduli spaces of curves. Hangzhou, China.
**

**
Sept. 11-13, 2008, invited speaker,
Ricci flow in mathematics and physics , University of Strasbourg, France.
my talk
**

**
Jan. 8, 2007, AMS special session invited speaker. My talk
"
the cosine law and volume" .
New Orleans, LA.
**

**
March. 15, 2007, colloquium speaker, Boston College,
"rigidity of polyhedral surfaces" .
**

**
April 12-14, 2007, invited speaker,
ASPECTS OF TEICHMUELLER THEORY,
University of Michigan.
**

**
April 28-29, 2007, invited speaker,
"Pacific Northwest
Geometry
Seminar" Univ. of Utah.
**

**
May 20-26, 2007, invited speaker,
"BRAIDS AND THEIR RAMIFICATIONS"
Cortona, Italy.
**

**
May 30-June 3, 2007, invited speaker,
"A second time around the volume conjecture"
Louisiana State University.
.
**

**
June 18-22, 2007, speaker and co-organizer,
"Geometric topology"
Beijing, China
.
**

**
June 25-30, 2007, speaker and co-organizer,
Geometric topology and geometric analysis , CMS, Zhejiang University, Hangzhou, China.
**

**
July 16-20, 2007, invited speaker,
"Discrete Differential Geometry"
Berlin, Germany.
**

**
July 27-31, 2007, speaker and co-organizer,
International Conference on Topology and Physics - In Memory of Xiao-Song Lin,
Tianjin, China.
**

** Oct. 20-21, invited speaker,
"workshop on geometric evolution equations", UC San Diego.
**

**
Dec. 17-22, 2007, invited plenary speaker,
"The fourth International Congress of Chinese Mathematicians", Hangzhou, China.
**

**
2006
**

**
March 6-10, 2006, invited speaker, Oberwolfach workshop
Discrete differential geometry.
My talk "some applications of the cosine law" .
**

**
March 16-19, 2006, invited speaker (two lectures),
Geometric Group Theory on the Gulf Coast.
**

**
May 17-21, 2006, invited speaker,
Georgia Topology Conference .
**

** Oct. 27-29, 2006, invited speaker,
Texas Geometry and Topology Conference . My talk
"volume and angle structures on 3-manifolds".
**

**
**

**
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