4 problems

Kim–Livingston's conjecture. If $M$ is algebraically nullbordant, then $M$ is nullbordant in $\widehat{\Theta}_3^\mathbb{Q}$.

Let $K$ be a knot in $S^3$. A lensbordant surgery on $K$ is a positive integer surgery that is smoothly rational homology cobordant to a lens space, and let $u^+(K)$ denote the kn…

Let $\Theta^3_\mathbb{Q}$ be the rational homology cobordism group of rational homology 3-spheres. A nontrivial torsion element of $\Theta^3_\mathbb{Q}$ should have order two. Two-…

Let $\widehat{\Theta}^3_{\mathbf Q}$ denote the topological cobordism group of rational homology three-spheres, and let $W(\mathbf Q/\mathbf Z)$ be the Witt group of nonsingular…