Branching analysis of a countable family of global similarity solutions of a fourth-order thin film equation Articles uri icon

publication date

  • April 2015

start page

  • 1

end page

  • 29


  • 90


  • 2015

International Standard Serial Number (ISSN)

  • 1072-6691


  • The main goal in this article is to justify that source-type and other global-in-time similarity solutions of the Cauchy problem for the fourthorder thin film equation can be obtained by a continuous deformation (a homotopy path). This is done by reducing to similarity solutions (given by eigenfunctions of a rescaled linear operator B) of the classic bi-harmonic equation This approach leads to a countable family of various global similarity patterns of the thin film equation, and describes their oscillatory sign-changing behaviour by using the known asymptotic properties of the fundamental solution of bi-harmonic equation. These include, as a key part, the problem of multiplicity of solutions, which is under particular scrutiny.


  • thin film equation; cauchy problem; source-type similarity solutions; finite interfaces; oscillatory sign-changing behaviour; hermitian spectral theory; branching