Rice's theorem comments on the undesirability of non-trivial semantic properties, however there are syntactic properties that are undecidable as well, such as the "useless" states problem for Turing Machines.
What are some undecidable syntactic properties?
Can we comment on the undecidability of a syntactic property based on the nature of the TMs that fall under it?
I am not sure if this question is a duplicate of this, especially since I am referring to syntactic properties, not non-semantic ones. If it is, I'm looking for a more comprehensive answer than the one given there, or atleast an answer to the first point.
