Rump, Siegfried M.Siegfried M.Rump2021-02-052021-02-052003IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences 9 (E86-A): 2357-2359 (2003)http://hdl.handle.net/11420/8702The concept of an Ω-matrix was introduced by Nishi in order to estimate the number of solutions of a resistive circuit containing active elements. He gave a finite characterization by means of four conditions which are all satisfied if and only if the matrix under investigation is an Ω-matrix. In this note we show that none of the four conditions can be omitted.en1745-13372003923572359IEICEP-matrixResistive circuitΩ-matrixInformatikMathematikJournal ArticleOther