User blog comment:PsiCubed2/Question: General breakdown of levels up to Second Order Arithmetic/@comment-30118230-20180204192313/@comment-30754445-20180205093150

The first 4 don't seem to intimidating. If I'm not mistaken, Π11-TR0 has a PTO of ψ(ψɪ(0)). This doesn't even get us nontrivial reflections, so obviously it is very very far from Π12-CA0.

Three more questions here:

1. What's the PTO of Δ12-CA+BI? Or is it so strong that nobody knows?

2. Is there such a thing as Δ12-TR0?

3. A bit unrelated, but what's the PTO of Π11-CA?