Non-existence of a short algorithm for multiplication of $3\times3$ matrices with group $S_4\times S_3$, II (2211.04032v1)

Abstract: It is proved that there is no an algorithm for multiplication of $3\times3$ matrices of multiplicative length $\leq23$ that is invariant under a certain group isomorphic to $S_4\times S_3$. The proof makes use of description of the orbits of this group on decomposable tensors in the tensor cube $(M_3({\mathbb C}))^{\otimes3}$ which was obtained earlier.