These problems pages are part of the Electronic Journal of Differential Equations. Here you can read problems proposed by others and solutions provided by readers or the editors.

You can submit a problem for these pages by emailing it to

Phil Kormanor Junping Shi (College of William and Mary)or Steve Pelikanor Dieter Schmidt

Include simple TeX/LaTeX/AMSTeX/LAMSTeX in your letter, or send a plain text file attachement that is a tex/latex/amstex/lamstex file. Please do NOT use special macros or LaTeX definitions. Please do NOT send files in other formats (such as dvi, ps, pdf).

You can also submit solutions by email to the above addresses.

A star (*) following the problem number indicates that neither the proposer nor the editors have the solution to the problem.

**Current Problems** *Submit solutions by
July 1, 2011.*

**(2011-1) **( Proposed by Cezar Lupu,
student, University of Bucharest, Bucharest and Vicentiu Radulescu, Institute of Mathematics
``Simion Stoilow" of the Romanian Academy, Bucharest, Romania.).

**(2011-2) **( Proposed by Ovidiu Furdui,
Campia-Turzii, 405100, Cluj, Romania).

**(2011-3) **( Proposed by Cezar Lupu,
student, University of Bucharest, Bucharest and Vicentiu Radulescu, Institute of Mathematics
``Simion Stoilow" of the Romanian Academy, Bucharest, Romania.).

**(2011-4) **( Proposed by Duong Viet Thong,
Department of Economics Mathematics,
National Economics University,
207 Giai Phong Road, Hai Ba Trung District, Hanoi, Vietnam).