Sorry for the naive question. Is it theoretically possible that
a statement such as "there are infinitely many primes of the form n^2+1"
could be true, but not provable, in ZFC?

I'm well aware that there are going to be statements in mathematics which
are true but not provable, but on the other hand I also am half-aware that
it's too naive to expect that an *arbitrary* statement...

I would like to announce a website created by Robert Samal and myself:
The Open Problem Garden

http://garden.irmacs.sfu.ca

The Open Problem Garden is a collection of unsolved problems in
mathematics (presently biased toward discrete math). It is a wiki in
the sense that our users may contribute new problems and may edit
existing ones (easy registration required).

We are keen to grow, so we eagerly invite contributions from all areas
of mathematics.

Regards,
Matt DeVos