| Vol-2908 urn:nbn:de:0074-2908-7 Copyright © 2021 for the individual papers by the papers' authors. Copyright © 2021 for the volume as a collection by its editors. This volume and its papers are published under the Creative Commons License Attribution 4.0 International (CC BY 4.0).

# SMT 2021
Satisfiability Modulo Theories 2021

### Proceedings of the 19th International Workshop on Satisfiability Modulo Theories
co-located with 33rd International Conference on Computer Aided Verification(CAV 2021)

### Online (initially located in Los Angeles, USA), July 18-19, 2021.

Edited by

### Alexander Nadel *
Aina Niemetz **

* Intel, Haifa, Israel
** Stanford University, Stanford, USA

## Table of Contents

- Preface
  Summary: There were 16 papers submitted for peer-review to this workshop: 11 as presentation-only paper, 5 as extended abstract and 2 original papers. Out of these, 6 papers are published in this volume, 2 as regular papers and 4 as extended abstracts. Also included in this volume are abstracts for the 2 invited talks given at the workshop, and the abstracts of 2 papers that were submitted for presentation only. For the remaining presentation-only papers, we provide the references below.

### Invited Talks

- Invited Talk: Using SMT and Abstraction-Refinement for Neural Network Verification 1
  Guy Katz
- Invited Talk: AVR: Word-Level Verification by Equality Abstraction of Data State 2
  Karem A. Sakallah

### Extended Abstracts

- Proof Tree Preserving Sequence Interpolation of Quantified Formulas in the Theory of Equality 3-16
  Elisabeth Henkel, Jochen Hoenicke, Tanja Schindler
- First-Order Instantiation using Discriminating Terms 17-22
  Chad Brown, Mikoláš Janota
- Further Steps Down The Wrong Path: Improving the Bit-Blasting of Multiplication 23-31
  Martin Brain
- Dolmen: A Validator for SMT-LIB and Much More 32-39
  Guillaume Bury

### Regular Papers

- AXDInterpolator: A Tool for Computing Interpolants for Arrays with MaxDiff 40-52
  Jose Abel Castellanos Joo, Silvio Ghilardi, Alessandro Gianola, Deepak Kapur
- Characteristic Subsets of SMT-LIB Benchmarks 53-63
  Jan Jakubův, Mikoláš Janota, Andrew Reynolds

### Presentation-Only Papers (Abstracts)

- Abstract: Reliable Reconstruction of Fine-Grained Proofs in a Proof Assistant 64
  Hans-Jörg Schurr, Mathias Fleury, Martin Desharnais
- Abstract: The Extended Theory of Trees and Algebraic (Co)datatypes 65
  Fabian Zaiser, Luke Ong

### Presentation-Only Papers (References)

- Politeness and Stable Infiniteness: Stronger Together (paper published at CADE 2021, available here)
  Ying Sheng, Yoni Zohar, Christophe Ringeissen, Andrew Reynolds, Clark Barrett, Cesare Tinelli
- Quantifier Simplification by Unification in SMT (paper to appear at FROCOS 2021)
  Hans-Jörg Schurr, Pascal Fontaine
- On Symmetry and Quantification: A New Approach to Verify Distributed Protocols (paper published at NFM 2021, available here)
  Aman Goel, Karem A. Sakallah
- Counterexample-Guided Prophecy for Model Checking Modulo the Theory of Arrays (paper published at TACAS 2021, available here)
  Makai Mann, Ahmed Irfan, Alberto Griggio, Oded Padon, Clark Barrett
- Theory-Specific Proof Steps Witnessing Correctness of SMT Executions (paper to appear at DAC 2021, available here)
  Rodrigo Otoni, Martin Blicha, Patrick Eugster, Antti E. J. Hyvärinen, Natasha Sharygina
- Smt-Switch: A Solver-agnostic C++ API for SMT Solving (paper published at SAT 2021)
  Makai Mann, Amalee Wilson, Yoni Zohar, Lindsey Stuntz, Ahmed Irfan, Kristopher Brown, Caleb Donovick, Allison Guman, Cesare Tinelli, Clark Barrett

2021-07-14: submitted by Aina Niemetz, metadata incl. bibliographic data published under Creative Commons CC0
2021-07-15: published on CEUR Workshop Proceedings (CEUR-WS.org, ISSN 1613-0073) |valid HTML5|