Gereon Kremer

Researcher on SMT at Certora

I'm working as a researcher in the SMT team at Certora. Certora offers one of the leading solutions for formally verifying Ethereum smart contracts used for decentralized financial applications. The focus of the SMT team is to improve the SMT backend of the Certora Verification Tool to enhance scalability, robustness and usefulness for the end user.

Previously, I was a postdoctoral researcher at the Center for Automated Reasoning at Stanford University advised by Clark Barrett after working as a researcher at RWTH Aachen University in the Theory of Hybrid Systems group led by Erika Ábrahám where I also did my PhD about using Cylindrical Algebraic Decomposition for SMT solving.

research interests

  • Satisfiability Modulo Theories (SMT)
  • Techniques for Nonlinear Arithmetic
  • Cylindrical Algebraic Decomposition
  • Automated Testing and Debugging

Education

  • PhD (Dr. rer. nat) in Computer Science, 2020

    RWTH Aachen University

  • MSc in Computer Science, 2013

    RWTH Aachen University

  • BSc in Computer Science, 2011

    RWTH Aachen University

Projects

Certora Prover

Verifies EVM bytecode with respect to a specification written in the Certora Verification Language

docs.certora.com
cvc5

An efficient open-source automatic theorem prover for satisfiability modulo theories (SMT) problems

cvc5/cvc5
cvc5.github.io
ddSMT

A delta debugger for SMT-LIBv2

ddsmt/ddSMT
ddsmt.readthedocs.io
SMT-RAT

An SMT solver with special focus on Nonlinear Real Arithmetic

smtrat/smtrat
CArL

A C++ library for Computer ARithmetic and Logic

smtrat/carl
libpoly

A C library for manipulating polynomials

SRI-CSL/libpoly
deprecated
CVC4

An efficient open-source automatic theorem prover for satisfiability modulo theories (SMT) problems

CVC4/CVC4-archived
cvc4.github.io
download
Satisfiability Modulo Finite Fields // The Certora Prover

September 2024, TUM Blockchain Conference, Munich, Germany

download recording
Satisfiability Modulo Theories: Using OS to solve hard problems

August 2023, FrOSCon

download
Cooperating Techniques for Solving Nonlinear Real Arithmetic in the cvc5 SMT Solver

August 2022, International Joint Conference on Automated Reasoning, Haifa, Israel

download
Cylindrical Algebraic Coverings for Quantifiers

August 2022, Satisfiability Checking and Symbolic Computation, Haifa, Israel

download recording
Satisfiability Modulo Theories for Arithmetic Problems

June 2022, Global Virtual SageDays, the world

download
Solving nonlinear real arithmetic in cvc5

May 2022, CENTAUR group meeting, Stanford, USA

download
Formal proofs for Cylindrical Algebraic Coverings

February 2022, New Perspectives in Symbolic Computation and Satisfiability Checking, Dagstuhl, Germany

download
On the Implementation of Cylindrical Algebraic Coverings for Satisfiability Modulo Theories Solving

December 2021, Symbolic and Numeric Algorithms for Scientific Computing, West University of Timisoara, Romania

download
Implementing arithmetic over algebraic numbers: A tutorial for Lazard's lifting scheme

December 2021, Symbolic and Numeric Algorithms for Scientific Computing, West University of Timisoara, Romania

Publications

see all publications

Other activities

FrOSCon

Co-organizer of the Free and Open Source Software Conference since 2015

Conference reviews

FM'24, SCSC'24, SCSC'23, NFM'23, SCSC'22, IJCAR'22, CAV'21, ISSAC'21, SMT'21, FMCAD'20, WRLA'20, FMCAD'19, iFM'19, LPAR-22, NFM'18, HSCC'17, MACIS'17, TMPA'17, VMCAI'17, FM'16, SMT'16, ATVA'15, FM'15, TACAS'15, VMCAI'15, FTSCS'14, HSCC'14

Journal reviews

JSC 2016, 2018, 2019, FMSD 2021, 2024, MCS 2024

Teaching assistance
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Supervised thesis projects
  • Master download A novel adaption of the simplex algorithm for linear real arithmetic. Jasper Nalbach, 2020, supervised with Erika Ábrahám.
  • Master download Conflict driven cylindrical algebraic coverings for nonlinear arithmetic in SMT solving. Hanna Franzen, 2020, supervised with Erika Ábrahám.
  • Bachelor download SMT-basierte Lösung reell-algebraischer Probleme mittels Linearisierung. Denis Kuksaus, 2019, supervised with Erika Ábrahám.
  • Master download Incremental linearization for SAT modulo real arithmetic solving. Aklima Zaman, 2019, supervised with Erika Ábrahám.
  • Master download Linearization techniques for nonlinear arithmetic problems in SMT. Ömer Sali, 2018, supervised with Erika Ábrahám.
  • Bachelor download Quantifier elimination by cylindrical algebraic decomposition. Tom Neuhäuser, 2018, supervised with Erika Ábrahám.
  • Master download Using equational constraints in an incremental CAD projection. Rebecca Haehn, 2018, supervised with Erika Ábrahám.
  • Master download Using single CAD cells as explanations in MCSAT-style SMT solving. Malte Neuß, 2018, supervised with Erika Ábrahám.
  • Bachelor download Using Fourier-Motzkin variable elimination for MCSAT explanations in SMT-RAT. Lorena Calo Bartolomé, 2018, supervised with Erika Ábrahám.
  • Master download Automated optimization in production planning. Henri Lotze, 2018, supervised with Erika Ábrahám.
  • Bachelor download Implementing an incremental solver for difference logic. Christopher Lösbrock, 2018, supervised with Erika Ábrahám, Matthias Volk.
  • Bachelor download Computing minimal infeasible subsets for the cylindrical algebraic decomposition. Wanja Hentze, 2017, supervised with Erika Ábrahám.
  • Bachelor download Solving pseudo-Boolean constraints. Marta Grobelna, 2017, supervised with Erika Ábrahám.
  • Bachelor download Using Thom encodings for real algebraic numbers in the cylindrical algebraic decomposition. Tobias Winkler, 2016, supervised with Erika Ábrahám.
  • Bachelor download Comparing different projection operators in the cylindrical algebraic decomposition for SMT solving. Tarik Viehmann, 2016, supervised with Erika Ábrahám.
  • Bachelor download SMT-based planning for autonomous robot fleets. Leonard Korp, 2016, supervised with Erika Ábrahám, Francesco Leofante.
  • Bachelor download Generation of infeasible subsets in less-lazy SMT-solving for the theory of uninterpreted functions. Lukas Neuberger, 2015, supervised with Erika Ábrahám.
  • Master download Bitvectors in SMT-RAT and their application to integer arithmetics. Andreas Krüger, 2015, supervised with Erika Ábrahám.