EDIT: I thought on rephrasing the question in another way: I have been working recently with a tensor that satisfies $A_{ijkl}=A_{i+b,j+b,k+b,l+b}$ $\forall$ $i,j,k,l$ $\in$ Z $$dist(i,j,k,l)\leq M$$ where all indices are meant to be integers (also b with $b\geq 0$), and dis(i,j,k,l) is the distance between all pair of indices, so $|i-j|\leq M$, $|i-k|\leq M$ etc... with 6 total distances. Because of this symmetry, it is said that one can just fix one of the values of the indices, say $i=0,1,..,b-1$ and generate the other elements from the symmetry relation above. I am struggling to see this, as for example, considering the case of a matrix $C_{i+b,j+b}=C_{i,j}$ it is clear to me how can one do this: one just calculates values for a single row, say $i=0$ and since $C_{ij}=0\forall |i-j|>M$, one is left with $2M+1$ independent terms. Then, the rest of matrix elements can be derived by using the symmetry relation: $$C_{i+b,j+b}=C_{i,j}$$ However, for the $A$ tensor above I am having difficulties to see this and how one could in principle recover all the missing elements of the set, if I set $i=0$ and calculate for the other indices. How can one get, for example $A_{1,1,2,3}$ if we only now those terms for $i=0$ ( that is, we know $A_{0,jkl}$ only ) for the case $b=1$? Thanks !!