Proof of the Chua conjecture on LTC-realizable resistive n-ports

In a recent paper Chua proved that a large class of voltage-controlled nonlinear resistive -ports could be realized with the aid of a homeomorphic resistive -port and a linear transformation converter (LTC) constructed of negative linear resistors. He conjectured that only such resistors are needed. In addition to proving this conjecture, we demonstrate that the resistors need not be negative.