3 problems

A Poincare 4-ball is a contractible 4-manifold whose boundary is $S^3$. A Schoenflies 4-ball is a Poincare 4-ball that embeds in $S^4$. Poincare ball 5-ball conjecture. If…

Smooth Poincaré conjecture in dimension 4. There are no exotic $S^4$'s; equivalently,

González-Acuña's conjecture. If $A$ is an Artin $n$-presentation such that $|A|=1$, then $A\sim T$. This is one of the conjectures relating Artin presentations of the trivial group…