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  • Research Article
  • Open Access

Nielsen number and differential equations

Fixed Point Theory and Applications20052005:268678

  • Received: 19 July 2004
  • Published:


In reply to a problem of Jean Leray (application of the Nielsen theory to differential equations), two main approaches are presented. The first is via Poincaré's translation operator, while the second one is based on the Hammerstein-type solution operator. The applicability of various Nielsen theories is discussed with respect to several sorts of differential equations and inclusions. Links with the Sharkovskii-like theorems (a finite number of periodic solutions imply infinitely many subharmonics) are indicated, jointly with some further consequences like the nontrivial -structure of solutions of initial value problems. Some illustrating examples are supplied and open problems are formulated.

Authors’ Affiliations

Department of Mathematical Analysis and Mathematical Applications, Faculty of Science, Palacký University, Tomkova 40, Olomouc-Hejčín, 779 00, Czech Republic


© Andres 2005