THORN is proved sound

[dr.mt...@gmail.com]

I have to check a couple of details but it looks as if

we're there.  What this means is that if THORN 

says something follows, it actually does follow.

It's probably clear why this is important, but briefly

w.o. that proof we could not trust the results of 

CST and the huge proofs coming out of it.

The soundness proof - which takes about 2 sides of A4 -

is the coda to this work.

M.