## ex--Miscellaneous Examples

This directory presents a number of small examples, illustrating various features of Isabelle/HOL.

- `Classical` demonstrates the power of Isabelle's classical reasoner.
- Files `mesontest.ML` and `mesontest2.ML` present an implementation of the Model Elimination (ME) proof procedure, which is even more powerful than the classical reasoner but not generic.
- `InSort` and `Qsort` are correctness proofs for sorting functions.
- `Primrec` proves that Ackermann's function is not primitive recursive.
- `Tarski` is a proof of Tarski's fixedpoint theorem: the full version, which states that the fixedpoints of a complete lattice themselves form a complete lattice. The example demonstrates first-class reasoning about theories.
- `NatSum` demonstrates the power of permutative rewriting. Well-known identities about summations are proved using just induction and rewriting.
- `MT` is a preliminary version of Jacob Frost's coinduction example. The full version is on the directory `ZF/Coind`.

Last modified on $Date: 2005/03/07 18:19:12 $