https://blog.leavitt.dev/tags/z3/ Recent content in Z3 on Corey Leavitt Hugo en-us Tue, 08 Sep 2026 00:00:00 +0000 https://blog.leavitt.dev/posts/nelli-sound-integer-abstraction/ Tue, 08 Sep 2026 00:00:00 +0000 https://blog.leavitt.dev/posts/nelli-sound-integer-abstraction/ A symbolic executor has to encode every integer for the solver. Bit-vectors are correct but slow; unbounded integers are fast but unsound. nelli runs on bit-vectors and abstracts to unbounded integers only where it can prove the abstraction is safe. https://blog.leavitt.dev/posts/nelli-one-engine/ Wed, 26 Aug 2026 00:00:00 +0000 https://blog.leavitt.dev/posts/nelli-one-engine/ nelli is a Nim testing library built on a choice-sequence engine. Because a test input is just a recorded sequence of typed choices, the same engine drives property testing, coverage-guided fuzzing, and SMT-backed symbolic execution.