M. Clapp and A. Szulkin, Non-variational weakly coupled elliptic systems. [Preprint]
M. Clapp and A. Szulkin, Solutions to indefinite weakly coupled cooperative elliptic systems, Topol. Meth. Nonl. Anal., to appear. [Preprint]
J. Mederski and A. Szulkin, A Sobolev-type inequality for the curl operator and ground states for the curl-curl equation with critical exponent, Arch. Rat. Mech. Anal. 241 (2021), 1815-1842. [Preprint]
M. Clapp, A. Saldaña and A. Szulkin, Phase separation, optimal partitions and nodal solutions to the Yamabe equation on the sphere, Int. Math. Res. Notices 2021:5 (2021), 3633-3652. [Preprint]
J. Mederski, J. Schino and A. Szulkin, Multiple solutions to a nonlinear curl-curl problem in R^3. Arch. Rat. Mech. Anal. 236 (2020), 253-288. [Preprint]
A. Szulkin and M. Willem, On some weakly coercive quasilinear problems with forcing, J. Analyse Math. 140 (2020), 267-281. [Preprint]
M. Clapp and A. Szulkin, A simple variational approach to weakly coupled competitive elliptic systems, Nonl. Diff. Eq. Appl. 26:26 (2019), 21 pp. [Preprint]
F.O. de Paiva, W. Kryszewski and A. Szulkin, Generalized Nehari manifold and semilinear Schrödinger equation with weak monotonicity condition on the nonlinear term, Proc. AMS 145 (2017), 4783-4794. [Preprint]
C. Ji and A. Szulkin, A logarithmic Schrödinger equation with asymptotic conditions on the potential, J. Math. Anal. Appl. 437 (2016), 241-254. [Preprint]
M. Clapp, A. Pistoia and A. Szulkin, Ground states of critical and supercritical problems of Brezis-Nirenberg type, Ann. Mat. Pura Appl. 195 (2016), 1787-1802. [Preprint]
W. Kryszewski and A. Szulkin, Bifurcation from infinity for an asymptotically linear Schrödinger equation, J. Fixed Point Theory Appl. 16 (2014), 411-435. [Preprint]
M. Squassina and A. Szulkin, Multiple solutions to logarithmic Schrödinger equations with periodic potential, Calc. Var. PDE 54 (2015), 585-597, [Erratum]. [Preprint]
M. Clapp and A. Szulkin, A supercritical elliptic problem in a cylindrical shell. In: Analysis and Topology in Nonlinear Differential Equations, D.G. de Figueiredo et al. eds, Birkhäuser, Basel, 2014, pp. 233-242. [Preprint]
Y. Jalilian and A. Szulkin, Infinitely many solutions for semilinear elliptic problems with sing-changing weight functions, Applicable Analysis 93 (2014), 756-770. [Preprint]
M. Clapp and A. Szulkin, Multiple solutions to nonlinear Schrödinger equations with singular electromagnetic potential, J. Fixed Point Theory Appl. 13 (2013), 85-102. [Preprint]
X.D. Fang and A. Szulkin, Multiple solutions for a quasilinear Schrödinger equation, J. Diff. Eq. 254 (2013), 2015-2032. [Preprint]
N. Ackermann and A. Szulkin, A concentration phenomenon for semilinear elliptic equations, Arch. Rat. Mech. Anal. 207 (2013), 1075-1089. [Preprint]
A. Szulkin and S. Waliullah, Infinitely many solutions for some singular elliptic problems, Discrete and Continuous Dynamical Systems, Ser. A, 13 (2013), 321-333. [Preprint]
A. Szulkin and S. Waliullah, Sign-changing and symmetry-breaking solutions to singular problems, Complex Variables and Elliptic Equations 57 (2012), 1191-1208. [Preprint]
A. Szulkin and T. Weth, The method of Nehari manifold. In: Handbook of Nonconvex Analysis and Applications, D.Y. Gao and D. Motreanu eds., International Press, Boston, 2010, pp. 597-632. [Preprint]
M. Clapp and A. Szulkin, Multiple solutions to a nonlinear Schrödinger equation with Aharonov-Bohm magnetic potential, Nonl. Diff. Eq. Appl. 17 (2010), 229-248. [Preprint]
W. Kryszewski and A. Szulkin, Infinite-dimensional homology and multibump solutions, J. Fixed Point Theory Appl. 5 (2009), 1-35. [Preprint]
A. Szulkin, T. Weth and M. Willem, Ground state solutions for a semilinear problem with critical exponent, Diff. Int. Eq. 9-10 (2009), 913-926. [Preprint]
M. Clapp, R. Iturriaga and A. Szulkin, Periodic and Bloch solutions to a magnetic nonlinear Schrödinger equation, Adv. Nonl. Studies 9 (2009), 639-655. [Preprint]
A. Szulkin and T. Weth, Ground state solutions for some indefinite variational problems, J. Func. Anal. 257 (2009), 3802-3822. [Preprint]
J. Chabrowski, A. Szulkin and M. Willem, Schrödinger equation with multiparticle potential and critical nonlinearity, Topol. Meth. Nonl. Anal. 34 (2009), 201-211. [Preprint]
G. Arioli, A. Szulkin and W. Zou, Multibump solutions and critical groups, Trans. Amer. Math. Soc. 361 (2009), 3159-3187. [Preprint]
T. Bartsch, A. Szulkin and M. Willem, Morse theory and nonlinear differential equations. In: Handbook of Global Analysis, D. Krupka and D. Saunders eds., Elsevier, Amsterdam, 2008, pp. 41-73. [Preprint]
Y. Ding and A. Szulkin, Bound states for semilinear Schrödinger equations with sign-changing potential, Calc. Var. PDE 29 (2007), 397-419. [Preprint]
Y. Ding and A. Szulkin, Existence and number of solutions for a class of semilinear Schrödinger equations. In: Contributions to Nonlinear Analysis. A tribute to D.G. de Figueiredo on the Occasion of his 70th Birthday, T. Cazenave et al. eds., Birkhäuser, Basel, 2006, pp. 221-231. [Preprint]
T. Bartsch and A. Szulkin, Hamiltonian systems: periodic and homoclinic solutions by variational methods. In: Handbook of Differential Equations. Ordinary Differential Equations, Vol. 2, A. Cañada, P. Drábek and A. Fonda eds., Elsevier, Amsterdam, 2005, pp. 77-146. [Preprint]
K. Perera and A. Szulkin, p-Laplacian problems where the nonlinearity crosses an eigenvalue, Discrete and Continuous Dynamical Systems, Ser. A., 13 (2005), 743-753. [Preprint]
J. Chabrowski and A. Szulkin, On the Schrödinger equation involving a critical exponent and magnetic field, Topol. Meth. in Nonl. Anal. 25 (2005), 3-21. [Preprint]
A. Szulkin, A semilinear Schrödinger equation with magnetic field. In: Topological Methods, Variational Methods and their Applications, H. Brézis, K.C. Chang, S.J. Li and P. Rabinowitz eds., World Scientific, New Jersey, 2003, pp. 223-230. [Preprint]
G. Arioli and A. Szulkin, A semilinear Schrödinger equation in the presence of a magnetic field, Arch. Rat. Mech. Anal. 170 (2003), 277-295. [Preprint]
G. Li and A. Szulkin, An asymptotically periodic Schrödinger equation with indefinite linear part, Comm. Contemp. Math. 4 (2002), 763-776. [Preprint]
J. Chabrowski and A. Szulkin, On a semilinear Schrödinger equation with critical Sobolev exponent, Proc. Amer. Math. Soc. 130 (2002), 85-93. [Preprint]
W. Zou and A. Szulkin, Homoclinic orbits for asymptotically linear Hamiltonian systems, J. Func. Anal. 187 (2001), 25-41. [Preprint]
W. Zou and A. Szulkin, Infinite dimensional cohomology groups and periodic solutions of asymptotically linear Hamiltonian systems, J. Diff. Eq. 174 (2001), 369-391. [Preprint]
A. Szulkin and M. Willem, Eigenvalue problems with indefinite weight, Studia Math. 135 (1999), 191-201. [Preprint]
G. Arioli and A. Szulkin, Homoclinic solutions of Hamiltonian systems with symmetry, J. Diff. Eq. 158 (1999), 291-313. [Preprint]
A. Szulkin, Generalized linking theorem and nonlinear equations in unbounded domains. In: Equadiff 9, Proceedings, R.P. Agarwal, F. Neuman and J. Vosmanský eds., Masaryk University, Brno, 1998, pp. 159-168. [Preprint]
G. Arioli and A. Szulkin, Periodic motions of an infinite lattice of particles: the strongly indefinite case, Ann. Sci. Math. Québec 22 (1998), 97-119. [Preprint]
W. Kryszewski and A. Szulkin, Generalized linking theorem with an application to semilinear Schrödinger equation, Adv. Diff. Eq. 3 (1998), 441-472. [Preprint]