[lou1306]

> Yes, by restricting things to a non-Turing Complete subset.

No, not necessarily. There are procedures that _can_ verify properties against Turing-complete and even infinite-state systems. It's just that no _general_ (as in, sound and complete) procedure can exist.

[tsimionescu]

If it's not sound, than the result is meaningless. If it is not complete, then it only works on a subset of problems, which is equivalent to what I said.

[lou1306]

Agree that soundness is desirable, but "it only works on a subset of instances" and "you are restricted to a non-Turing complete subset" are not equivalent in the slightest.

[lostmsu]

Not sure what are you trying to say. Surely the "subset of instances" is non-Turing complete.