Juergen wrote >> BM: >> Tell me what you don't understand in my UDA post (which is the beginning >> of the shortest proof I know). >> UDA is at http://www.escribe.com/science/theory/m1726.html > >I did look at it and found lots of words but no formal proof, >although it does say "QED" at some point.

I guess that by formal proof you mean proof (to formalise a proof is interesting only in proof theory ...) The UDA proof is presented in 15 steps. (it uses COMP and five supplementary hypothesis which are eliminated at the end). You can formalise easily (but tediously) the proof. It makes it very long and unreadable. It is useless because the formalisation appears eventually in the interview of the sound UTM ... What are you telling me ? That you don't understand the hypothesis, that you don't understand the first step, the second step ? Is it the use of some "folk psychology" expression like "to survive a visit to the doctor" ? Tell me and I will explain (next week because I will read my mail only the week-end until the end of february). There is nothing magical hidden in my reasoning, and I have no doubt you will understand it soon or late :-) (I surely agree that in some steps I am a little quick ; my pedagogical problem is that nobody agrees on which steps are easy or difficult). Bruno