Proof Pearl: Looping Around the Orbit
We reexamine the While combinator of higher-order logic (HOL) and introduce the For combinator. We argue that both combinators should be part of the toolbox of any HOL practitioner, not only because they make efficient computations within HOL possible, but also because they facilitate elegant inductive reasoning about loops. We present two examples that support this argument.
KeywordsPlanar Graph Induction Rule Loop Index Oriented Edge Loop State
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