  In the paper "Fast Fibonacci heaps with worst case extensions", we have
described heaps with both Meld-DecreaseKey and DecreaseKey interfaces, allowing
operations with guaranteed worst-case asymptotically optimal times. The paper
was intended to concentrate on the DecreaseKey interface, but it could be hard
to separate the two described data structures without careful reading. The
current paper's goal is not to invent a novel data structure, but to describe a
rather easy DecreaseKey version in a hopefully readable form. The paper is
intended not to require reference to other papers.
