On a ratio theorem for a class of nonlinear boundary value problems

C. Rogers, A. J. Bracken
1987 Quarterly of Applied Mathematics  
A generalization of Ussing's flux ratio theorem is established as a consequence of a symmetry property of a Green's function. Backlund transformations are then used to construct ratio theorems for certain nonlinear boundary value problems.
doi:10.1090/qam/872816 fatcat:m4aihwazrzdxhgi4anbkqza3tu