# Is P/poly known to be in RE?

Is P/poly known to be in RE? If yes what other classes is it known to be part of.

$$P/poly$$ is NOT a subset of $$RE$$. Specifically, the unary non-halting problem (i.e. given a Turing Machine encoded in unary, does it run forever?) is in $$P/poly$$ but not $$RE$$. In fact, every undecidable unary language is in $$P/poly$$.
• The standard halting problem is in RE (unless you are talking about the $\Pi_2$ complete problem of halting on all inputs). Of course any unary encoding of a language outside $RE$ will do. – Ariel Jun 11 at 19:26