Nikolaj Bjorner
Researcher at Microsoft USA
Redmond, Washington, United States
Summary
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Top expert inFunctional Programming and Formal Verification Technologies
Nikolaj Bjorner is a veteran researcher and software engineer with 13+ years at Microsoft in Redmond and a PhD in Computer Science from Stanford, specializing in formal methods and satisfiability solving. He is a core contributor to the widely used Z3 theorem prover, where his low-level work on SAT solving, quantifiers, proof logging, and performance optimizations (e.g., 64-bit trailing zeros) improved both efficiency and traceability. His background spans academia and industry research labs, with earlier roles at Kestrel Institute and XDegrees sharpening his focus on verification and logic-based tooling. Comfortable deep in systems and algorithms, he routinely translates theoretical insights into practical, production-grade code for verification benchmarks and SMT infrastructure. Colleagues rely on him for debugging complex solver internals and for making subtle, high-impact changes that rarely appear in surface-level project descriptions.
13 years of coding experience
7 years of employment as a software developer
N/A, Computer Science, N/A, Computer Science at DIKU - Datalogisk Institut, Koebenhavn's UniversitetN/A, Computer Science, N/A, Computer Science at Danish Technical UniversityDoctor of Philosophy (PhD), Computer Science, Doctor of Philosophy (PhD), Computer Science at Stanford University
English, Danish, French, German
Stackoverflow
146reputation
2kreached
3answers
0questions
Github Skills (13)
theorem-proving10
c-language10
formal-verification10
cprogramming-language10
logic10
logical9
symbolic-logic9
data-structure9
debug9
data-structures9
debugging9
algorithms9
z36
Programming languages (13)
Github contributions (5)
Z3Prover/z3
Oct 2012 - Jan 2023
The Z3 Theorem Prover
Role in this project:
Back-end Developer
Back-end DeveloperContributions:953 releases, 360 reviews, 10691 commits in 10 years 5 months
Contributions summary:Nikolaj contributed to the core functionality of Z3 theorem prover by addressing bugs, expanding functionalities, and incorporating new features. The commits reflect a strong understanding of the system's internal workings, including the SAT solver, arithmetic constraints, and data structures, as evidenced by changes in source files related to various components. The user implemented performance improvements, such as a 64-bit based trailing zeros method to enhance memory efficiency and runtime. Contributions also included work on quantifier handling and proof logging infrastructure to enhance traceability.
theorem-proverprovertheorem
sosy-lab/sv-benchmarks
Nov 2012 - Jan 2014
Collection of Verification Tasks
Role in this project:Back-end Developer
Back-end DeveloperContributions:26 commits in 1 year 1 month
Contributions summary:Nikolaj's commits primarily involve modifications to SMT2 files, which are likely verification tasks. The changes include altering code snippets and updating the formatting of the files. These modifications suggest a focus on the logical and algorithmic aspects of the verification tasks, improving their structure and potentially their performance within a verification framework.
securitytlaverification
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