In the paper by Shariff (Q. J. Mech. Appl. Math. 76, 143–161, 2023) a functional basis of vectors and symmetric tensors based on eigenvectors of the first tensor is proposed. In the paper by Itskov (Mech. Soft Mater. 6(4), 1–3, 2024) a counterexample is reported demonstrating that the proposed terms do not generally represent isotropic invariants and cannot thus serve as a functional basis of symmetric tensors. In the latest response (Mech. Soft Mater. 6, 4, 2024) Shariff shows many examples of symmetric tensors for which his functional basis is valid but he does not really oppose the counterexample.
