Algorithms for structured matrix-vector product of optimal bilinear complexity

We present explicit algorithms for computing structured matrix-vector products that are optimal in the sense of Strassen, i.e., using a provably minimum number of multiplications. These structures include Toeplitz/Hankel/circulant, symmetric, Toeplitz-plus-Hankel, sparse, and multilevel structures. The last category include $\text{textsc}bttb$, $\text{textsc}bhhb$, $\text{textsc}bccb$ but also any arbitrarily complicated nested structures built out of other structures.