Shyuichi, Izumiya et Bing, Li, Overdetermined Systems of First Order Partial Differential Equations with Singular Solution, Acta Mathematica Sinica, New Series Chinese Journal of Mathematics, 13(3), 1997, pp. 327-332
We study overdetermined systems of first order partial differential equations with singular solutions. The main result gives a characterization of such systems and asserts that the singular solution is equal to the contact singular set.