In this paper, we describe a hierarchy of program transformers in which the transformer at each level of the hierarchy builds on top of those at lower levels. The program transformer at level 1 of the hierarchy corresponds to positive supercompilation, and that at level 2 corresponds to distillation. We prove that the transformers at each level terminate. We then consider the speedups that can be obtained at each level in the hierarchy, and try to characterise the improvements that can be made.

翻译：在本文中, 我们描述一个程序变压器的等级, 使等级的各级变压器在较低等级的变压器之上建起。 等级的一级变压器对应正超合成, 2级的变压器对应蒸馏。 我们证明每个等级的变压器终止了。 然后我们考虑在等级的每个级别上可以得到的加速, 并尝试描述可以作出的改进。