Alloy+HotCore: A Fast Approximation to Unsat Core

Identifying a minimal unsatisfiable core in an Alloy model proved to be a very useful feature in many scenarios. We extend this concept to hot core, an approximation to unsat core that enables the user to obtain valuable feedback when the Alloy’s sat-solving process is abruptly interrupted. We present some use cases that exemplify this new feature and explain the applied heuristics. The NP-completeness nature of the verification problem makes hot core specially appealing, since it is quite frequent for users of the Alloy Analyzer to stop the analysis when some time threshold is exceeded. We provide experimental results showing very promising outcomes supporting our proposal.

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