Real linear Kronecker product operations

The Kronecker product in the real linear matrix analytic setting is studied. More versatile operations are proposed. Such generalizations are of interest for the same reasons the standard Kronecker product is. To give an example, new preconditioning ideas are suggested. In connection with this, several formulae for the inverse are devised. Orthogonal decompositions of real-entried matrices are derived through introducing new Kronecker product SVDs. Matrix equations are given to illustrate how the Kronecker product structures introduced can arise.