Exponential dimension conjecture for alternating multiple t-values

For each $n\ge2$, let $\mathsf{AMtV}_n$ denote the rational vector space of alternating multiple $t$-values of weight $n$. Exponential dimension conjecture.

$$\dim_{\mathbb Q}\mathsf{AMtV}_n=3\times2^{n-2}.$$

The paper lists this among three dimension conjectures supported by theoretical and numerical evidence, and states that these problems are unsolved.