A conjecture about multiple $t$-values

Abstract

For positive integers $a_1,\ldots,a_r$ with $a_1 \ge 2$, the multiple $t$-value $t(a_1,\ldots,a_r)$ is defined by the series $\sum\limits_{n_1 > \ldots > n_r > 0 \atop n_i \text{ odd}} n_1^{-a_1} \cdots n_r^{-a_r}$. For an integer $k \ge 2$, the dimension of the $\mathbb Q$-vector space generated by all the multiple $t$-values of weight $k$ has been predicted by Hoffman to be the $k$-th Fibonacci number. In this short note we give a conjectural basis of this vector space.