# Program

Click on one of the following links to get the program for your preferred time zone:

San Jose, UTC-7 | Waterloo, UTC-4 | Bath, UTC+1 | Lille, UTC+2 | Saint Petersburg, UTC+3 | Beijing, UTC+8 | Kobe, UTC+9 | ||

## Sunday 18th July 2021

Workshop in Honor of Vladimir Gerdt (room: W). Access the program.

## Monday 19th July 2021

Saint Petersburg, UTC+3 | Sessions | ||

13:50–14:00 | Conference opening + Announcements (room: P) | ||

Tutorial (chair: Carsten Schneider, room: P) | |||

14:00–16:00 | Pierre Vanhove – Differential Equations for Feynman Integrals | ||

16:00–16:30 | Break | ||

Tutorial (chair: Anton Leykin, room: P) | |||

16:30–18:30 | Janko Böhm and Anne Frühbis-Krüger – Massively Parallel Computations in Algebraic Geometry | ||

18:30–19:00 | Break | ||

Regular talks | |||

Session: linear algebra I (chair: Vincent Neiger, room: A) | Session: sparseness (chair: Michael Monagan, room: B) | ||

19:00–19:30 | Robert Corless, Leili Rafiee Sevyeri and Dave Saunders – Equivalences for linearizations of matrix polynomials |
Pascal Giorgi, Bruno Grenet and Armelle Perret du Cray – On exact division and divisibility testing for sparse polynomials | |

19:30–20:00 | Pierre Karpman, Clément Pernet, Hippolyte Signargout and Gilles Villard – Computing the characteristic polynomial of generic Toeplitz-like and Hankel-like matrices |
Mark Giesbrecht, Qiao-Long Huang and Éric Schost – Sparse multiplication of multivariate linear differential operators |

## Tuesday 20th July 2021

Saint Petersburg, UTC+3 | Sessions | ||

13:50–14:00 | Announcements (room: P) | ||

Regular talks | |||

Session: differential and difference algebra I (chair: Jürgen Gerhard, room: A) | Session: dynamical systems / optimization (chair: Mohab Safey El Din, room: B) | ||

14:00–14:30 | Shaoshi Chen, Ruyong Feng, Pingchuan Ma and Michael F. Singer – Separability problems in creative telescoping |
– | |

14:30–15:00 | Shinichi Tajima and Katsusuke Nabeshima – Computing Grothendieck point residues via solving holonomic systems of first order partial differential equations |
Ryoya Fukasaku – Criteria for Hopf bifurcations with fixed multiplicities | |

15:00–15:30 | Mawunyo Kofi Darkey-Mensah, Przemysław Koprowski and Beata Rothkegel – The anisotropic part of a quadratic form over a global function field |
Ngoc Hoang Anh Mai, Abhishek Bhardwaj and Victor Magron – The constant trace property in noncommutative optimization | |

15:30–16:00 | Thierry Combot – Elementary integration of superelliptic integrals |
Lorenzo Baldi and Bernard Mourrain – Computing real radicals by moment optimization | |

16:00–16:30 | Break | ||

Tutorial (chair: Jonathan Hauenstein, room: P) | |||

16:30–18:30 | Marc Moreno Maza – Design and Implementation of Multi-Threaded Algorithms in Polynomial Algebra | ||

18:30–19:00 | Break | ||

Maplesoft Demonstration (chair: Robert Corless, room: P) | |||

19:00–20:00 | Jürgen Gerhard – What’s New in Maple 2021? |

## Wednesday 21st July 2021

Saint Petersburg, UTC+3 | Sessions | ||

13:50–14:00 | Announcements (room: P) | ||

Invited talk (chair: Frédéric Chyzak, room: P) | |||

14:00–15:00 | Alin Bostan – Computer Algebra in the Service of Enumerative Combinatorics | ||

15:00–15:30 | Break | ||

Regular talks | |||

Session: lattices / discriminants (chair: Veronika Pillwein, room: A) | Session: linear algebra II (chair: Paola Boito, room: B) | ||

15:30–16:00 | Jianwei Li – On the smallest ratio problem of lattice bases |
Alexandre Sedoglavic and Alexey V. Smirnov – The tensor rank of $5\times5$ matrices multiplication is bounded by $98$ and its border rank by $89$ | |

16:00–16:30 | Erich Kaltofen – Computing higher polynomial discriminants |
Eleonora Guerrini, Romain Lebreton and Ilaria Zappatore – Polynomial linear system solving with random errors: new bounds and early termination technique | |

Business meetings (room: P) | |||

16:30–17:30 | ISSAC Business Meeting | ||

17:30–18:15 | SIGSAM Business Meeting | ||

Short Communications (chair: Hao Du, room: A) | Short Communications (chair: Wei Li, room: B) | ||

18:15–18:30 | Kosaku Nagasaka – Approximate GCD by relaxed NewtonSLRA algorithm |
Shashi Gowda, Yingbo Ma, Alessandro Cheli, Maja Gwóźdź, Viral Shah, Alan Edelman and Christopher Rackauckas – High-performance symbolic-numerics via multiple dispatch | |

18:30–18:45 | Mawunyo Kofi Darkey-Mensah – Algorithms for quadratic forms over global function fields of odd characteristic |
Daniel Miguel, Andrea Guidolin, Ana Romero and Julio Rubio – Constructing new spectral systems from simplicial fibrations | |

18:45–19:00 | Russell Bradford, James H. Davenport, Matthew England, Amirhossein Sadeghimanesh and Ali Uncu – The DEWCAD project: pushing back the doubly exponential wall of cylindrical algebraic decomposition |
Skander Belhaj and Abdulrahman Alsulami – Approximate greatest common divisor of several polynomials from Hankel matrices | |

Regular talks | |||

Session: bivariate polynomials (chair: Ioannis Emiris, room: A) | Session: algebraic numbers (chair: Dan Roche, room: B) | ||

19:00–19:30 | Seung Gyu Hyun, Vincent Neiger and Éric Schost – Algorithms for linearly recurrent sequences of truncated polynomials |
Nikhil Balaji, Sylvain Perifel, Mahsa Shirmohammadi and James Worrell – Cyclotomic identity testing and applications | |

19:30–20:00 | Joris van der Hoeven and Grégoire Lecerf – Amortized bivariate multi-point evaluation |
Fredrik Johansson – Calcium: computing in exact real and complex fields |

## Thursday 22nd July 2021

Saint Petersburg, UTC+3 | Sessions | ||

13:50–14:00 | Announcements (room: P) | ||

Regular talks | |||

Session: differential and difference algebra II / algebraic geometry (chair: Hui Huang, room: A) | Session: CAD, quantifier eliminations, logic I (chair: Thomas Sturm, room: B) | ||

14:00–14:30 | Taihei Oki – Computing valuations of the Dieudonné determinants |
Haokun Li, Bican Xia, Huiying Zhang and Tao Zheng – Choosing the variable ordering for cylindrical algebraic decomposition via exploiting chordal structure | |

14:30–15:00 | Shaoshi Chen, Lixin Du and Manuel Kauers – Lazy Hermite reduction and creative telescoping for algebraic functions |
Mikhail Starchak – Positive existential definability with unit, addition and coprimeness | |

15:00–15:30 | Jakob Ablinger and Carsten Schneider – Solving linear difference equations with coefficients in rings with idempotent representations |
Huu Phuoc Le and Mohab Safey El Din – Faster one block quantifier elimination for regular polynomial systems of equations | |

15:30–16:00 | Elie Eid – Fast computation of hyperelliptic curve isogenies in odd characteristic |
Kai Hormann, Lucas Kania and Chee Yap – Novel range functions via Taylor expansions and recursive Lagrange interpolation with application to real root isolation | |

16:00–16:30 | Break | ||

Regular talks | |||

Session: Gröbner bases for operads (chair: Manuel Kauers, room: A) | Session: CAD, quantifier eliminations, logic II (chair: Laura Kovács, room: B) | ||

16:30–17:00 | Andrey Cherkasov and Dmitri Piontkovski – Wilf classes of non-symmetric operads |
David Braun, Nicolas Magaud and Pascal Schreck – Two new ways to formally prove Dandelin-Gallucci's theorem | |

17:00–17:30 | Philippe Malbos and Isaac Ren – Completion in operads via essential syzygies |
Jasper Nalbach, Erika Ábrahám and Gereon Kremer – Extending the fundamental theorem of linear programming for strict inequalities | |

Software Presentations (chair: Wen-shin Lee, room: A) | Short Communications (chair: Jose Israel Rodriguez, room: B) | ||

17:30–17:45 | Ilia Ilmer, Alexey Ovchinnikov and Gleb Pogudin – Maple application for structural identifiability analysis of ODE models |
Andrei Matveiakin – Discovering multiple polylogarithm equations via symbolic computations | |

17:45–18:00 | Alexandre Goyer – A Sage package for the symbolic-numeric factorization of linear differential operators |
Eduardo Sáenz de Cabezón and Rodrigo Iglesias – Cellular reductions of the Pommaret-Seiler resolution for quasi-stable ideals | |

18:00–18:15 | Zoltán Kovács, Tomás Recio and M. Pilar Vélez – Automated reasoning tools in GeoGebra Discovery |
Julian Pfeifle – Large final polynomials from integer programming | |

18:15–18:30 | Philippe Elbaz-Vincent and Étienne Marcatel – An extension of the fpLLL library to Hermitian lattices |
Juan Ignacio García-García, Daniel Marín-Aragón and Alberto Vigneron-Tenorio – Computing the ideals of sumset semigroups | |

18:30–19:00 | Break | ||

Invited talk (chair: Éric Schost, room: P) | |||

19:00–20:00 | Nadia Heninger – Algorithmic Techniques and Open Problems in Cryptanalysis |

## Friday 23rd July 2021

Saint Petersburg, UTC+3 | Sessions | ||

13:50–14:00 | Announcements (room: P) | ||

Invited talk (chair: Ziming Li, room: P) | |||

14:00–15:00 | Xiao-shan Gao – New Developments of Mathematics Mechanization | ||

15:00–15:30 | Break | ||

Regular talks | |||

Session: Gröbner bases I (chair: Romain Lebreton, room: A) | Session: differential and difference algebra III (chair: Carlos Arreche, room: B) | ||

15:30–16:00 | Rina Dong, Dong Lu, Chenqi Mou and Dongming Wang – Comprehensive characteristic decomposition of parametric polynomial systems |
Antonio Jiménez-Pastor – Simple differentially definable functions | |

16:00–16:30 | Maria Francis and Thibaut Verron – On two signature variants of Buchberger's algorithm over principal ideal domains |
Joris van der Hoeven and Gleb Pogudin – A zero test for $\sigma$-algebraic power series | |

16:30–17:00 | Jérémy Berthomieu, Christian Eder and Mohab Safey El Din – msolve: a library for solving polynomial systems |
Raphaël Pagès – Computing characteristic polynomials of $p$-curvatures in average polynomial time | |

17:00–17:30 | Xavier Caruso, Tristan Vaccon and Thibaut Verron – On FGLM algorithms with Tate algebras |
Antonio Jiménez-Pastor, Philipp Nuspl and Veronika Pillwein – On $C^2$-finite sequences | |

17:30–18:00 | Break | ||

Regular talks | |||

Session: Gröbner bases II (chair: Jonathan Hauenstein, room: A) | Session: univariate polynomials (chair: Lihong Zhi, room: B) | ||

18:00–18:30 | Alexander Levin – Generalized Gröbner bases and new properties of multivariate difference dimension polynomials |
Erich Kaltofen, Clément Pernet and Zhi-Hong Yang – Hermite interpolation with error correction: fields of zero or large characteristic and large error rate | |

18:30–19:00 | Pierre Lairez and Mohab Safey El Din – Computing the dimension of real algebraic sets |
J. Maurice Rojas and Yuyu Zhu – A complexity chasm for solving univariate sparse polynomial equations over $p$-adic fields | |

19:00–19:15 | Awards Announcement + Conference close (room: P) |