References
- Ambrosetti , A. and Rabinowitz , P.H. 1973 . Dual variational methods in critical point theory and applications . J. Fund. Anal. , 14 : 349 – 381 .
- Berberian , S. 1967 . Measure and Integration , New York : Macmillan Co. .
- Chang , K.C. 1996 . Variational methods for non‐differentiable functionals and applications to partial differential equations . J. Math. Anal. Appl. , 80 : 102 – 129 .
- Clarke , F.H. 1975 . Generalized gradients and applications . Trans. Amer. Math. Soc , 205 : 247 – 262 .
- Clarke , F.H. 1981 . Generalized gradients of Lipschitz functionals . Adv. in Math. , 40 : 52 – 67 .
- Esry , B.D. , Greene , C.H. , Burke , J.P. Jr. and Bohn , J.L. 1997 . Hartree‐Fock theory for double condensates . Phys. Rev. Lett. , 78 : 3594 – 3597 .
- Gazzola , F. and Radulescu , V. 2000 . A nonsmooth critical point theory approach to some nonlinear elliptic equation in Rn . Differential and Integral Equations , 13 : 47 – 60 .
- Gilbarg , D. and Trudinger , N.S. 1998 . Elliptic Partial Differential Equations of Second Order , Berlin : Springer .
- Grosse , H. and Martin , A. 1997 . Particle Physics and the Schrodinger Equation , Cambridge Monographs on Particle Physics, Nuclear Physics and Cosmology, Cambridge Univ. Press .
- Hasegawa , A. and Kodama , Y. 1995 . Solitons in Optical Communications , San Diego : Academic Press .
- Hyers , D. , Isac , G. and Rassias , T. 1997 . Topics in Nonlinear Analysis and Applications , River Edge, NJ : World Scientific Publishing Co., Inc. .
- Islam , M.N. 1992 . Ultrafast Fiber Switching Devices and Systems , New York : Cambridge University Press .
- Kato , T. 1984 . “ Remarks on holomorphic families of Schrodinger and Dirac operators ” . In Differential equations , Edited by: Knowles , I. and Lewis , R. volume 92 , 341 – 352 . North‐Holland, Amsterdam : North‐Holland Math. Stud. .
- Mironescu , P. and Radulescu , V. 1995 . A multiplicity theorem for locally Lipschitz periodic functional . J. Math. Anal. Appl. , 195 : 621 – 637 .
- Oh , Y.‐G. 1988 . Existence of semi‐classical bound states of nonlinear Schrodinger equations with potentials of the class (va) . Communications on Partial Differential Equations , 13 : 1499 – 1519 .
- Rabinowitz , P.H. 1992 . On a class of nonlinear Schrodinger equations . Zeit. Angew. Math. Phys. (ZAMP) , 43 : 270 – 291 .
- Radulescu , V. 1993 . Mountain pass type theorems for non‐differentiable functions and applications . Proc. Japan Acad. , 69A : 193 – 198 .
- Sulem , C. and Sulem , P.‐L. 1999 . The Nonlinear Schrödinger Equation. Self‐focusing and Wave Collapse. Applied Mathematical Sciences , volume 139 , New York : Springer‐Verlag .
- This paper is dedicated to the memory of my father, Tudor Dinu.