### Abstract

In this submission array-based binary minimum heaps are formalized.
The correctness of the following heap operations is proved: insert,
get-min, delete-min and make-heap. These are then used to verify an
in-place heapsort. The formalization is based on IMP2, an imperative
program verification framework implemented in Isabelle/HOL. The
verified heap functions are iterative versions of the partly recursive
functions found in "Algorithms and Data Structures – The Basic
Toolbox" by K. Mehlhorn and P. Sanders and "Introduction to
Algorithms" by T. H. Cormen, C. E. Leiserson, R. L. Rivest and C.
Stein.