3 problems

Let $\lambda_n$ denote the $n$th Ohtsuki invariant of an integral homology 3-sphere. The source records the known facts $\lambda_1\in 6\mathbb Z$ and $\lambda_2\in 3\mathbb Z$. Lin…

Let ${\cal O}_k$ be the vector space of rational $\mathbb Z$-homology-sphere invariants of order at most $k$, and let ${\cal G}_n$ be the vector space of invariants of order at mos…

Let $Y$ be a homology $3$-sphere with $(Y)=0$, and let $\frak{ds}(Y)$ be finite. The bounding genus $|Y|$ is the invariant defined using homologically $1$-connected bounding $4$-ma…