Stabilizers for nondegenerate matrices of boundary format and Steiner bundles.
In this paper nondegenerate multidimensional matrices of boundary format in V ⊗ ... ⊗ V are investigated by their link with Steiner vector bundles on product of projective spaces. For any nondegenerate matrix A the stabilizer for the SL(V) x ... x SL(V)-action, Stab(A), is completely described. In particular we prove that there exists an explicit action of SL(2) on V ⊗ ... ⊗ V such that Stab(A) ⊆ SL(2) and the equality holds if and only if A belongs to a unique SL(V) x ... x SL(V)-orbit containing...