Abstract

The Knaster–Tarski theorem asserts the existence of least and greatest fixpoints for any monotonic function on a complete lattice. More strongly, it asserts the existence of a complete lattice of such fixpoints. This fundamental theorem has a fairly straightforward proof. We use a mechanically checked proof of the Knaster–Tarski theorem to illustrate several features of the Prototype Verification System (PVS). We specialize the theorem to the power set lattice, and apply the latter to the verification of a general forward search algorithm and a generalization of Dijkstra's shortest path algorithm. We use these examples to argue that the verification of even simple, widely used algorithms can depend on a fair amount of background theory, human insight, and sophisticated mechanical support.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.