L. Levi, FIRST-ORDER QUASI-LINEAR EQUATIONS WITH U NILATERAL CONSTRAINT, Comptes rendus de l'Academie des sciences. Serie 1, Mathematique, 317(12), 1993, pp. 1133-1136
The existence and uniqueness for a scalar conservation la,v related to
Dirichlet's homogeneous boundary conditions and to a simple obstacle
condition are established. Hence for the following problem: [GRAPHICS]
two methods are developed, either by penalizing the equation (E) or b
y approximating to U through a sequence of solutions of parabolic ineq
ualities related to a positivness constraint.