Thomas C. Hales

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Thomas C. Hales is an American mathematician renowned for his contributions to discrete geometry, representation theory, and formal verification. Born on June 4, 1958, Hales is best known for proving the Kepler Conjecture, a centuries-old problem in mathematics concerning the most efficient way to pack spheres in a given space.


Kepler Conjecture:
The Kepler Conjecture, proposed by Johannes Kepler in 1611, posits that no arrangement of equally sized spheres filling space has a greater average density than that of the face-centered cubic packing or hexagonal close packing. This problem remained unsolved for nearly 400 years. In 1998, Hales announced a proof of the conjecture. Due to the complexity of the proof—which combined traditional mathematical techniques with extensive computer verification—it underwent a rigorous and lengthy peer review process.


To address any remaining uncertainties, Hales initiated the Flyspeck Project (Formal Proof of Kepler), aiming to create a fully formalized and computer-verified proof of the Kepler Conjecture. In 2014, the project was successfully completed, providing a definitive verification and serving as a significant milestone in the field of formal methods and proof verification.


Honeycomb Conjecture:
In addition to his work on sphere packing, Hales also proved the Honeycomb Conjecture in 1999. This conjecture states that a regular hexagonal grid (like that seen in honeycomb structures) is the most efficient way to partition a surface into regions of equal area with the least total perimeter.


Academic Position and Contributions:
As a professor at the University of Pittsburgh, Hales continues to advance the fields of mathematics and computer science. His work emphasizes the importance of formal verification in mathematics, advocating for the use of computer-assisted proofs to enhance the rigor and reliability of mathematical results. He has published numerous papers and continues to contribute to research on representation theory and other areas of mathematics.


Hales's contributions have had a profound impact on mathematics, not only by resolving longstanding conjectures but also by pioneering methods that bridge traditional mathematics and computer science.

All published works
Action Title Year Authors
+ PDF A Review of Alfred North Whitehead’s “Introduction to Mathematics” 2024 Thomas Hales
+ PDF Chat A review of Alfred North Whitehead's "Introduction to Mathematics" 2024 Thomas Hales
+ PDF Chat The Formal Proof of the Kepler Conjecture: a critical retrospective 2024 Thomas C. Hales
+ PDF Chat Reminiscences by a Student of Langlands 2021 Thomas Hales
+ Formal Proof of the Group Law for Edwards Elliptic Curves 2020 Thomas C. Hales
Rodrigo Raya
+ PDF Formal Proof of the Group Law for Edwards Elliptic Curves 2020 Thomas C. Hales
Rodrigo Raya
+ Formal Proof of the Group Law for Edwards Elliptic Curves 2020 Thomas C. Hales
Rodrigo Raya
+ Reminiscences by a student of Langlands 2019 Thomas Hales
+ Exposé Bourbaki 1086 : Developments in formal proofs 2018 Thomas C. Hales
+ Walter Talbot's thesis 2018 Thomas C. Hales
+ PDF External Tools for the Formal Proof of the Kepler Conjecture 2018 Thomas C. Hales
+ Walter Talbot's thesis 2018 Thomas C. Hales
+ The spherical Hecke algebra, partition functions, and motivic integration 2017 W. Casselman
Jorge E. Cely
Thomas C. Hales
+ The Reinhardt Conjecture as an Optimal Control Problem 2017 Thomas C. Hales
+ PDF A FORMAL PROOF OF THE KEPLER CONJECTURE 2017 Thomas C. Hales
Mark Adams
Gertrud Bauer
TAT DAT DANG
John Harrison
Hoang Le Truong
Cezary Kaliszyk
Victor Magron
Sean McLaughlin
TAT THANG NGUYEN
+ The Reinhardt Conjecture as an Optimal Control Problem 2017 Thomas C. Hales
+ The Spherical Hecke algebra, partition functions, and motivic integration 2016 W. Casselman
Jorge E. Cely
Thomas C. Hales
+ The Group Law for Edwards Curves 2016 Thomas Hales
+ Packings of Regular Pentagons in the Plane 2016 Thomas C. Hales
Wöden Kusner
+ PDF Chat Endoscopic transfer of orbital integrals in large residual characteristic 2016 Julia Gordon
Thomas C. Hales
+ The Group Law for Edwards Curves 2016 Thomas Hales
+ The Spherical Hecke algebra, partition functions, and motivic integration 2016 W. Casselman
Jorge E. Cely
Thomas C. Hales
+ Endoscopic transfer of orbital integrals in large residual characteristic 2015 Julia Gordon
Thomas C. Hales
+ A formal proof of the Kepler conjecture 2015 Thomas Hales
Mark Adams
Gertrud Bauer
Dat Tat Dang
John Harrison
Hoang Le Truong
Cezary Kaliszyk
Victor Magron
Sean McLaughlin
Thang Tat Nguyen
+ Endoscopic transfer of orbital integrals in large residual characteristic 2015 Julia Gordon
Thomas C. Hales
+ A formal proof of the Kepler conjecture 2015 Thomas Hales
Mark Raymond Adams
Gertrud Bauer
Dat Tat Dang
John Harrison
Hoang Le Truong
Cezary Kaliszyk
Victor Magron
S. McLaughlin
Thang Tat Nguyen
+ Developments in Formal Proofs 2014 Thomas C. Hales
+ PDF Chat Mathematics in the age of the Turing machine 2014 Thomas C. Hales
+ Developments in Formal Proofs 2014 Thomas C. Hales
+ Mathematics in the Age of the Turing Machine 2013 Thomas Hales
+ PDF Chat The Strong Dodecahedral Conjecture and Fejes Tóth’s Conjecture on Sphere Packings with Kissing Number Twelve 2013 Thomas C. Hales
+ Homotopy Type Theory: Univalent Foundations of Mathematics 2013 Peter Aczel
Benedikt Ahrens
Thorsten Altenkirch
Steve Awodey
Bruno Barras
Andrej Bauer
Yves Bertot
Marc Bezem
Thierry Coquand
Eric Finster
+ PDF Chat Formal Verification of Nonlinear Inequalities with Taylor Interval Approximations 2013 Alexey Solovyev
Thomas Hales
+ Mathematics in the Age of the Turing Machine 2013 Thomas Hales
+ A Proof of Fejes Toth's Conjecture on Sphere Packings with Kissing Number Twelve 2012 Thomas C. Hales
+ Trigonometry 2012 Thomas C. Hales
+ Credits 2012 Thomas C. Hales
+ Dense Sphere Packings 2012 Thomas C. Hales
+ Preface 2012 Thomas C. Hales
+ Dense Sphere Packings: A Blueprint for Formal Proofs 2012 Thomas C. Hales
+ A Proof of Fejes Toth's Conjecture on Sphere Packings with Kissing Number Twelve 2012 Thomas C. Hales
+ The Strong Dodecahedral Conjecture and Fejes Toth's Contact Conjecture 2011 Thomas C. Hales
+ On the Reinhardt Conjecture 2011 Thomas C. Hales
+ The fundamental lemma and the Hitchin fibration [after Ngo Bao Chau] 2011 Thomas C. Hales
+ A Formulation of the Kepler Conjecture 2011 Thomas C. Hales
Samuel P. Ferguson
+ A Revision of the Proof of the Kepler Conjecture 2011 Thomas C. Hales
John Harrison
Sean McLaughlin
Tobias Nipkow
Steven Obua
Roland Zumkeller
+ Sphere Packings, I 2011 Thomas C. Hales
+ Interactive Theorem Proving 2011 Jeremy Avigad
Thomas C. Hales
Vladimir Voevodsky
+ The Mathematical Work of the 2010 Fields Medalists 2011 Thomas C. Hales
B. P. Weiss
Wendelin Werner
Luigi Ambrosio
+ Sphere Packings, VI. Tame Graphs and Linear Programs 2011 Thomas C. Hales
+ Sphere Packings, IV. Detailed Bounds 2011 Thomas C. Hales
+ Historical Overview of the Kepler Conjecture 2011 Thomas C. Hales
+ Sphere Packings, III. Extremal Cases 2011 Thomas C. Hales
+ On the Reinhardt Conjecture 2011 Thomas C. Hales
+ The Strong Dodecahedral Conjecture and Fejes Toth's Conjecture on Sphere Packings with Kissing Number Twelve 2011 Thomas C. Hales
+ The fundamental lemma and the Hitchin fibration [after Ngo Bao Chau] 2011 Thomas C. Hales
+ The Work of Ngo Bao Chau 2010 Thomas C. Hales
+ Linear Programs for the Kepler Conjecture 2010 Thomas C. Hales
+ The Work of Ngo Bao Chau 2010 Thomas C. Hales
+ Linear Programs for the Kepler Conjecture - (Extended Abstract). 2010 Thomas C. Hales
+ PDF The dodecahedral conjecture 2009 Thomas C. Hales
Sean McLaughlin
+ A Revision of the Proof of the Kepler Conjecture 2009 Thomas C. Hales
John Harrison
Sean McLaughlin
Tobias Nipkow
Steven Obua
Roland Zumkeller
+ A revision of the proof of the Kepler conjecture 2009 Thomas Hales
John Harrison
Sean McLaughlin
Tobias Nipkow
Steven Obua
Roland Zumkeller
+ Equidecomposable Quadratic Regions 2007 Thomas C. Hales
+ PDF The Jordan Curve Theorem, Formally and Informally 2007 Thomas C. Hales
+ Transfer Principle for the Fundamental Lemma 2007 Raf Cluckers
Thomas C. Hales
François Loeser
+ Some Methods of Problem Solving in Elementary Geometry 2007 Thomas C. Hales
+ PDF Sphere Packing, III. Extremal Cases 2006 Thomas C. Hales
+ PDF Sphere Packing, IV. Detailed Bounds 2006 Thomas C. Hales
+ PDF Historical Overview of the Kepler Conjecture 2006 Thomas C. Hales
+ PDF A Formulation of the Kepler Conjecture 2006 Thomas C. Hales
Samuel P. Ferguson
+ Introduction to the Flyspeck Project 2006 Thomas C. Hales
+ PDF A proof of the Kepler conjecture 2005 Thomas C. Hales
+ PDF What is motivic measure? 2005 Thomas C. Hales
+ Introduction to the Flyspeck Project. 2005 Thomas C. Hales
+ Orbital integrals are motivic 2004 Thomas C. Hales
+ Good orbital integrals 2004 Clifton Cunningham
Thomas C. Hales
+ None 2004 Clifton Cunningham
Thomas C. Hales
+ Formalizing the Proof of the Kepler Conjecture 2004 Thomas C. Hales
+ PDF Virtual transfer factors 2003 Julia Gordon
Thomas C. Hales
+ None 2003 Julia Gordon
Thomas C. Hales
+ A Statement of the Fundamental Lemma 2003 Thomas C. Hales
+ A computer verification of the Kepler conjecture 2003 Thomas Hales
+ What is Motivic Measure? 2003 Thomas C. Hales
+ Good orbital integrals 2003 Clifton Cunningham
Thomas C. Hales
+ The Honeycomb Problem on the Sphere 2002 Thomas C. Hales
+ Sphere Packings in 3 Dimensions 2002 Thomas C. Hales
+ Can p-adic integrals be computed? 2002 Thomas C. Hales
+ Orbital Integrals are Motivic 2002 Thomas C. Hales
+ Virtual Transfer Factors 2002 Julia Gordon
Thomas C. Hales
+ Some algorithms arising in the proof of the Kepler conjecture 2002 Thomas C. Hales
+ Sphere packings and generative 2001 Thomas C. Hales
+ PDF The Honeycomb Conjecture 2001 Thomas C. Hales
+ PDF Advances in random matrix theory, zeta functions, and sphere packing 2000 Thomas C. Hales
Peter Sarnak
M. C. Pugh
+ The Honeycomb Conjecture 1999 Thomas C. Hales
+ The Honeycomb Conjecture 1999 Thomas C. Hales
+ The Kepler conjecture 1998 Thomas C. Hales
+ Sphere packings III 1998 Thomas C. Hales
+ Sphere packings IV 1998 Thomas C. Hales
+ An overview of the Kepler conjecture 1998 Thomas C. Hales
+ A proof of the dodecahedral conjecture 1998 Thomas C. Hales
Sean McLaughlin
+ A formulation of the Kepler conjecture 1998 Samuel P. Ferguson
Thomas C. Hales
+ The Kepler conjecture 1998 Thomas Hales
+ Sphere packings I 1998 Thomas Hales
+ Sphere packings II 1998 Thomas Hales
+ Sphere packings IV 1998 Thomas Hales
+ Sphere packings III 1998 Thomas C. Hales
+ PDF The fundamental lemma for $Sp(4)$ 1997 Thomas C. Hales
+ PDF Sphere packings, I 1997 Thomas C. Hales
+ PDF On the Fundamental Lemma for Standard Endoscopy: Reduction to Unit Elements 1995 Thomas C. Hales
+ The twisted endoscopy of GL(4) and GL(5): transfer of Shalika germs 1994 Thomas C. Hales
+ The status of the kepler conjecture 1994 Thomas C. Hales
+ Hyperelliptic curves and harmonic analysis (why harmonic analysis on reductive 𝑝-adic groups is not elementary) 1994 Thomas C. Hales
+ Unipotent Representations and Unipotent Classes SL(N) 1993 Thomas C. Hales
+ Remarks on the density of sphere packings in three dimensions 1993 Thomas C. Hales
+ A simple definition of transfer factors for unramified groups 1993 Thomas C. Hales
+ The sphere packing problem 1992 Thomas C. Hales
+ The Subregular Germ of Orbital Intervals 1992 Thomas C. Hales
+ The subregular germ of orbital integrals 1992 Thomas C. Hales
Common Coauthors
Commonly Cited References
Action Title Year Authors # of times referenced
+ The Kepler conjecture 1998 Thomas C. Hales
16
+ The sphere packing problem 1992 Thomas C. Hales
15
+ PDF Sphere packings, I 1997 Thomas C. Hales
14
+ On the definition of transfer factors 1987 R. P. Langlands
D. Shelstad
9
+ Uniform p-adic cell decomposition and local zeta functions. 1989 Johan Pas
9
+ PDF Flyspeck II: the basic linear programs 2009 Steven Obua
Tobias Nipkow
8
+ Remarks on the density of sphere packings in three dimensions 1993 Thomas C. Hales
8
+ PDF A proof of the Kepler conjecture 2005 Thomas C. Hales
8
+ PDF A Formulation of the Kepler Conjecture 2006 Thomas C. Hales
Samuel P. Ferguson
7
+ The status of the kepler conjecture 1994 Thomas C. Hales
7
+ Descent for Transfer Factors 2007 R. P. Langlands
D. Shelstad
7
+ A proof of the dodecahedral conjecture 1998 Thomas C. Hales
Sean McLaughlin
7
+ PDF Guest Editors' Foreword 2006 GĂĄbor TĂłth
Jeffrey C. Lagaria
7
+ PDF A new bound on the local density of sphere packings 1993 Douglas J. Muder
6
+ PDF On the Fundamental Lemma for Standard Endoscopy: Reduction to Unit Elements 1995 Thomas C. Hales
6
+ PDF What are all the best sphere packings in low dimensions? 1995 John H. Conway
N. J. A. Sloane
6
+ The Problem of the Thirteen Spheres 1956 John Leech
5
+ Intégrales orbitales nilpotentes et endoscopie pour les groupes classiques non ramifiés 2001 Jean-Loup Waldspurger
5
+ Finite Groups of Lie Type: Conjugacy Classes and Complex Characters 1993 Roger W. Carter
5
+ Isoperimetric Inequalities and the Dodecahedral Conjecture 1997 KĂĄroly Bezdek
5
+ PDF Chat Germs of arcs on singular algebraic varieties and motivic integration 1999 Jan Denef
François Loeser
5
+ Definable sets, motives and 𝑝-adic integrals 2000 Jan Denef
François Loeser
5
+ Introduction to the Flyspeck Project 2006 Thomas C. Hales
5
+ A simple definition of transfer factors for unramified groups 1993 Thomas C. Hales
5
+ PDF Some applications of Bruhat-Tits theory to harmonic analysis on the Lie algebra of a reductive p-adic group 2002 Jeffrey D. Adler
Stephen DeBacker
4
+ Computational Real Algebraic Geometry 2004 Bud Mishra
4
+ Stable trace formula: Elliptic singular terms 1986 Robert Kottwitz
4
+ Le lemme fondamental pour les groupes unitaires 2004 GĂ©rard Laumon
B. C. NgĂŽ
4
+ Motivic integration and the Grothendieck group of pseudo-finite fields 2002 Jan Denef
François Loeser
4
+ PDF Homotopy theoretic models of identity types 2008 Steve Awodey
Michael A. Warren
4
+ Formalizing plane graph theory : towards a formalized proof of the Kepler conjecture 2006 Gertrud Bauer
4
+ PDF Chat Constructible motivic functions and motivic integration 2008 Raf Cluckers
François Loeser
4
+ Transfer factors for Lie Algebras 1999 Robert Kottwitz
4
+ Ternary cubic forms having bounded invariants, and the existence of a positive proportion of elliptic curves having rank 0 2010 Manjul Bhargava
Arul Shankar
4
+ Orbital Integrals on Forms of SL(3), I 1983 R. P. Langlands
4
+ On some rational generating series occuring in arithmetic geometry 2004 Jan Denef
François Loeser
4
+ An overview of the Kepler conjecture 1998 Thomas C. Hales
4
+ A STABLE TRACE FORMULA. I. GENERAL EXPANSIONS 2002 James Arthur
4
+ Flyspeck I: Tame Graphs 2006 Tobias Nipkow
Gertrud Bauer
Paula Schultz
4
+ PDF Homogeneity results for invariant distributions of a reductive p-adic group1 2002 Stephen DeBacker
4
+ PDF Soap bubbles in ℝ<sup>2</sup>and in surfaces 1994 Frank Morgan
3
+ The minimum value of quadratic forms, and the closest packing of spheres 1929 H. F. Blichfeldt
3
+ A Revision of the Proof of the Kepler Conjecture 2009 Thomas C. Hales
John Harrison
Sean McLaughlin
Tobias Nipkow
Steven Obua
Roland Zumkeller
3
+ PDF Constructible exponential functions, motivic Fourier transform and transfer principle 2010 Raf Cluckers
François Loeser
3
+ On the Degree of Igusa's Local Zeta Function 1987 Jan Denef
3
+ PDF A normal form for elliptic curves 2007 Harold M. Edwards
3
+ Kepler’s conjecture: How some of the greatest minds in history helped solve one of the oldest math problems in the world 2004 Karl Sigmund
3
+ Geometric Measure Theory 1988 Herbert Fédérer
3
+ Semidefinite programming relaxations for semialgebraic problems 2003 Pablo A. Parrilo
3
+ The minimum values of positive quadratic forms in six, seven and eight variables 1935 H. F. Blichfeldt
3