I'd appreciate some help for the following exercise:
Construct a (as simple as possible) deductive system where all sequences of the form 1n (which means 111... n-times) is provable if and only if n is not prime. (Note: As simple as possible means that the deductive rules and axioms should follow a simple schema. For example the schema "1n
is an axiom iff n is prime" isn't considered simple)
There is already an answered question to the problem of finding a similar deductive system in case n is not prime. Construct a deductive system where $1^n$ is provable iff $n$ is prime I am also interested in the solution to that problem, because I don't understand the notation in the answer (i.e. I don't know, what lt, ndiv, ndivsmaller etc means) and I can't simply write a comment there to clear that, because my reputation isn't high enough to do so yet.
Thank you in advance!