I don't know enough about propagator systems to know if there is a mismatch between what MJD and GJS are talking about. I do know that GJS's propagator model d

I don't know enough about propagator systems to know if there is a mismatch between what MJD and GJS are talking about. I do know that GJS's propagator model does more than the simple Farenheit-Celsius conversion problems (this example is actually in SICP chapter 3, but not in this paper), such as tracking the reasons why cells hold the data they do and withstanding logical contradictions.